Demographics of Poland
According to GUS, about 38,325,000 people live in Poland, however, the same report states that the number of residents living in the country all the time is approximately 37,200,000; with 1,125,000 people living abroad for 6 to 7 months or more. It means that the permanent population may be correspondingly smaller.
Second Polish Republic
Historically, Poland was a nation of many nationalities. This was especially true after independence was regained in the wake of World War I and the subsequent Polish–Soviet War ending at Peace of Riga. The census of 1921 shows 30.8% of the population consisted of ethnic minorities, compared with a share of 1.6% (solely identifying with a non-Polish ethnic group) or 3.8% (including those identifying with both the Polish ethnicity and with another ethnic group) in 2011. The first spontaneous flight of about 500,000 Poles from the Soviet Union occurred during the reconstitution of sovereign Poland. In the second wave, between November 1919 and June 1924 some 1,200,000 people left the territory of the USSR for Poland. It is estimated that some 460,000 of them spoke Polish as the first language. According to the 1931 Polish Census: 68.9% of the population was Polish, 13.9% were Ukrainian, around 10% Jewish, 3.1% Belarusian, 2.3% German and 2.8% other, including Lithuanian, Czech, Armenian, Russian, and Romani. The situation of minorities was a complex subject and changed during the period.
Poland was also a nation of many religions. In 1921, 16,057,229 Poles (approx. 62.5%) were Roman (Latin) Catholics, 3,031,057 citizens of Poland (approx. 11.8%) were Eastern Rite Catholics (mostly Ukrainian Greek Catholics and Armenian Rite Catholics), 2,815,817 (approx. 10.95%) were Greek Orthodox, 2,771,949 (approx. 10.8%) were Jewish, and 940,232 (approx. 3.7%) were Protestants (mostly Lutheran).