World population through the ages - GIF

[Frank S]

one billion in 1804;
two billion in 1927 (123 years later);
three billion in 1960 (33 years later);
four billion in 1974 (14 years later);
five billion in 1987 (13 years later);
six billion in 1999 (12 years later);
seven billion in October 2011 (12 years later);
eight billion on November 15, 2022 (11 years later).