World Population Timeline (Billions)
| World Population Timeline Milestones in Billions | |||||||||
| Population | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| Year | 1804 | 1927 | 1959 | 1974 | 1987 | 1999 | 2011 | 2022 | 2037 (projected) |
| Years elapsed | –– | 123 | 32 | 15 | 13 | 12 | 12 | 11 | 15 |
| World Population Timeline Milestones in Billions | |||||||||
| Population | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| Year | 1804 | 1927 | 1959 | 1974 | 1987 | 1999 | 2011 | 2022 | 2037 (projected) |
| Years elapsed | –– | 123 | 32 | 15 | 13 | 12 | 12 | 11 | 15 |