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