Its geopolitical significance since ancient times brought representatives of ethnic groups from all over Europe, Asia, and Africa, many of whom became assimilated with the local Greek and later Turkish populations.
The following overview shows the numbers of inhabitants by year[citation needed]. Population tallies up to 1914 are estimated with variations of up to 50% depending upon researcher. The numbers from 1927 to 2000 are results of censuses. The numbers of 2005 and 2006 are based on computer simulation forecasts. The doubling of the population of Istanbul between 1980 and 1985 is due to a natural increase in population as well as the expansion of municipal limits.