This article pertains only to the population growth of humans.
Prior to the first census in LY 905, records had never been kept of how many people were living on The Land at any give time, or in any particular village. Therefore, most population numbers or growth rates listed in this article are merely conjecture based on various historical records of events which in many cases are at best tangentially related to population.
It has long been estimated that around the time Brist conceived religion in LY 100, there were between 100 and 150 people living on the Land, which might be considered consistent with the long-held belief that when Connor and Brigid were created by God, they were the only two people in the world, and that they were from Day One of potential reproductive (apparent) age, assuming they had at least one child every two years, and that the next generation also produced at a similar rate once they grew to reproductive (actual) age, and assuming there were no fatalities at least until the deaths of Connor and Brigid, who are known to have died in the year 52. It would, alternatively, also be consistent with the revelation in 912 that in fact Connor and Brigid were created as babies on Day One, but that they were only two among an unknown number of other babies God created that day (it is commonly conjectured that the number was fifty). This would allow for a smaller annual population growth rate (around 1%), assuming the first generation didn't begin reproducing until something like year 15 to 20.
It is a matter of record that the original settlers of the Land's second village, Tonad, numbered 50, in LY 225, and that within a few years of its founding, several hundred more people moved there from First Village. It is unknown exactly how many people ended up living in each village by the time emigration effectively ended, but it is estimated that the total population of both villages combined was between 1000 and 1200, by the year 230, which would indicate an annual growth rate of around 1.5%.
If it can be assumed that the growth rate held steady at 1.5%, the world population when Sorret was founded in LY 271 would have been around 2300. If it had risen to, say, 2%, the world population may have been closer to 3000.
It is commonly believed that the world population around the time of the founding of Ship in LY 360 was about 8000 to 8500, indicating an average growth rate of around 1.2% between 271 and 360. The population in 380 is believed to have been about 9000 to 9500, with a growth rate around 0.5%. The 20-year period between the founding of Ship (the Land's fourth village) and Tanq (the Land's twelfth village) was the most active period of territorial expansion in the world's history. Normally when a new village is founded, there is an increase in the birth rate, believed to be caused by settlers' desire to grow their new village's population to something approximating that of their home village. While this factor was no doubt in effect between 360 and 380, it was more than offset by a couple of other factors. One was that 360 was the start of the Age of Sail, and with the advent of this new career, as more and more people became sailors, they spent less time at home than people ever had before. This led to fewer opportunities for procreation, and therefore a decreased birthrate. The second factor is that this period also represented the first great age of pirates, and battles at sea led to a higher mortality rate than usual.
It is known that none of the villages founded during the period of rapid expansion consisted of fewer than 500 settlers, and that even by the end of the expansion period, there were at least 1000 people remaining in each of the first three villages. This means that in LY 280, the world population consisted of at least 7500 people, but as noted earlier, historians' estimates place the population closer to 9500.
By the time Monab was founded in LY 404, the total world population could not have been more than 12,000, indicating an average growth rate of about 1% between 380 and 404. That rate is believed to have held steady until the founding of Plist in LY 500... with one notable exception. While specific numbers of births and deaths were not normally counted, history books make note of the peculiar fact that there was not a single birth or death in the year LY 436. (Some have suggested this was somehow related to the playing of an infamous game of Surreal that year, though this explanation seems unlikely. There are no other theories, however, other than the suggestion that it's purely random coincidence.) In any event, the world population in LY 500 is estimated at around 30,000.
While the founding of Plist inspired the usual surge in birthrate for the first decade of the sixth century, a general sense of boredom set in, which caused more people than any other century in the Land's history to become adventurers. Adventuring also seems to have become more dangerous about halfway into the century than it had been in the past, a fact which wouldn't be fully understood until the revelation of the creation of mythical creatures, in 595. Of course, adventurers were still in the minority, compared to traditional occupations, but even those with safe jobs seemed to have less interest in procreation than people of previous generations. And so, for these and undoubtedly other reasons (which would be impossible to guess at), historians believe the average population growth between 500 and 600 fell to an average of about 0.8%, making the population in LY 600 about 65,000 to 70,000.
If this rate had held steady over the next two years, the population by the end of 602 should have been on the order of 66,000 to 71,000. However, there is evidence to suggest about 10,000 more deaths occurred in that two-year period than would normally be expected, leaving the estimated world population somewhat under 60,000 in 602. There are no clear historical records of what might account for these deaths. Some historians believe that a rogue Sorreter named Xerxes, who is credited with the creation of ogres, used his creation as an army in an attempted conquest of the world (which would make that conquest, rather than the Coming of the Order, the first war in the history of the Land). While few would dispute that Xerxes actually existed, and was probably the one who created the first generation of ogres, the majority of historians consider the suggestion of war between ogres and humanity to be utterly implausible. Surely, they say, there would be irrefutable records, if such a thing had truly happened. Alternate theories explain the deaths as the result of a plague or natural disaster, though historians who espouse these theories cannot explain why there are no records of any such events, either.
The average population growth over the next 169 years, until the founding of Triscot in LY 771, presumably fluctuated from year to year, though with no major events to cause major deviation, apparently stayed fairly close to 1%. So, the world population is believed to have been between 300,000 and 325,000, by that point. The rate continued to hold fairly steady until LY 805, when the largest hurricane in recorded history hit the East Isles and Ship, resulting in an estimated 20,000 deaths (about half of them occurring in Frinn and Toobay). By the end of that year, world population was at an estimated 400,000 to 420,000 people.
The average growth rate between 806 and the founding of Ristar in 850 is estimated at around 0.7% resulting in an estimated world population of around 570,000. It must be noted that while the first age of piracy ended around LY 379, it never ended completely; hence the continued need for the Coast Guard. However, with the founding of Ristar, piracy began to incrementally increase, ultimately resulting in the second age of piracy, which is generally considered to have begun around LY 900. The increased mortality rate due to pirate attacks lowered the estimated population growth rate to an average of 0.5% over those 50 years, and it lowered more sharply from 900 onward. Additionally, the rise of inter-village gangs, beginning in 899, further contributed to the increased death rate. It is commonly estimated by historians that the world population at the start of LY 903 was around 740,000.
LY 903 saw the first officially recognized war on the Land, the Coming of the Order. It resulted in an estimated 16,000 deaths (total on both sides of the conflict), though some people have estimated there to have been up to twice as many deaths. The first census in 905 found there to be 484,991 humans in the world, which is at least 220,000 shy of historians' estimates (after subtracting war-related fatalities). It is also estimated that there are something like 50,000 to 70,000 rats on the Land, the majority of whom were probably not included in the census, which might bring the discrepancy down to around 150,000. It can be further reduced by remembering that the census did not include Shanty; it is unknown how many people may live there, but it is not believed to be more than 10,000, and probably less than that. A few hundred Sorreters had disappeared from the Battle of Triscot in 903, and so were not counted. And any number of other people may live "between villages" and so were missed unintentionally. Still others may have intentionally avoided the census-takers, for various reasons.
Even considering all these factors, there remains a discrepancy of over 100,000 people unaccounted for by the census, which most people- including historians themselves- ascribe to the fact that up til 905, everything was guesswork. And at that, the guesses were made by people who lived hundreds of years after the people they were guessing about. And of course, the slightest miscalculation on growth rates could represent a great discrepancy in the assumed number of actual population. However, ever since the first census, hospitals have been keeping records of births and deaths, to compare against the results of the second census, in LY 915, though since the Secession Referendum of 913, there has been much dispute as to the possible efficacy of any census which must be conducted within not just one country, but two, plus the now sovereign village of Sorret.