[1] http://history.stackexchange.com/questions/17465/yearly-popu...
[2] http://faculty.econ.ucdavis.edu/faculty/gclark/210a/readings...
[0] http://news.nationalgeographic.com/news/2014/09/140918-popul...
And, because you mentioned the end of the century, there is still »The Limits to Growth« and it predictions. I am actually not sure on which side I am here. I can't really imagine a collapse of society as we know it in the second half of the century but I am also aware of the sudden and unexpected behavior of complex systems and how hard it is to counteract a system with a lot of inertia. But if the predications come true, population control may become an issue sooner than we like.
http://www.google.co.uk/search?q=human+population+growth&prm...
Which population is that? Certainly not humans.