This article presents the demographic history of Bulgaria. See Demographics of Bulgaria
31 December 1920 census.
1. During the period 1910 - 1920 Bulgaria suffered physical loss of population as follows:
2. During the period 1910 - 1920 the population growth in Bulgaria was as follows:
31 December 1946 census.
South Dobruja passes on the territory of Bulgaria.
There are strong indications that in the 1946 census the population was forced to list as ethnic Macedonians against their will by the communist government in accordance with an agreement with Yugoslavia.
1 December 1956 census.
There are strong indications that in the 1956 census the population was forced to list as ethnic Macedonians against their will by the communist government in accordance with an agreement with Yugoslavia.
1 February 2011 census.
The 2011 percentage of the ethnic groups is calculated only from those who answered the optional question on ethnicity (6,680,980 in total) and does not include around 750,000 people who did not answer the question or 10% from the population.