Estimated world population (in millions) taken from Wikipedia
1000	310
1750	791
1800	978
1850	1262
1900	1650
1950	2518.6
1955	2755.8
1960	2981.7
1965	3334.9
1970	3692.5
1975	4068.1
1980	4434.7
1985	4831.0
1990	5263.6
1995	5674.4
2000	6070.6
2005	6453.6
