| Year | Population | Year | Population | Year | Population |
| Prior to 1000 AD | 300m | 1750 | 800m | 1800 | 1b (4m p.a.) |
| 1930 | 2b (7.7m p.a.) (*) | 1940 | 2.3b (30m p.a.) | 1960 | 3b (35m p.a.) (**) |
| 1974 | 4b (~71.4m p.a.) | 1987 | 5b (77m p.a.) | 1999 | 6b (82m p.a.) |
| 2018 | 7.7b est. |
| (*) impact of 1st WW | (**) impact of 2nd WW |
|