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Summary
DescriptionCountries by percentage of Protestants 1938.svg
English: This map shows countries by percentage of Protestants around 1938. Data from official censuses or estimates by various researches/authors/other experts on the subject for each country/territory were used. Overall, data from 1920-1950 was used, mainly aiming for the year 1938 (i.e. if 1925 and 1936 data was available, 1936 data was chosen to be used here). Few countries in Europe had a close to 10% Protestant community, specifically Czechoslovakia and Romania. In Czechoslovakia, the Czechoslovak Church may or may not be considered Protestant. By 1938, Protestant minorities in those countries may have grown to 10-20%. Estimates for Africa/Oceania region are difficult to obtain and are of the worst quality as most of them was made largely using the late 20th/early 21st century spread to predict how it would look like around 1938; also taking into account maps showing European colonization in Africa.
Legend:
90%-100%
80%-90%
70%-80%
60%-70%
50%-60%
40%-50%
30%-40%
20%-30%
10%-20%
Below 10% or no data
Some countries have percentages. These are countries where Protestant communities may have been more than their level shown on the map given their demographic growth (for example, Czechoslovakia has 0-10% (circa 7.7%), but it could be 10-20%) by 1938; though in several countries percentages are placed just to ensure religious situation there which has been exaggerated by some sources ("10% Protestant" in Lithuania according to an English language source, totally false; a 1932 book by German author K. F. Otto Losch states 3.3% which is far more possible) - this applies to Austria, Poland, Lithuania. To see percentages for blurry cases, look at Canada and Eastern Europe.
Official statistics for France do not exist since it prohibited keeping official religious statistics since 1872. Most probable set of percentages for Western Europe is 0-1% for each country (more closer to 0% than 1%) with possible exceptions of Belgium 3%, France and Luxembourg - both 2%. Note that these are only estimates and not official data.
Note that religion was overall suppressed in the Soviet Union. In 1897, during the Russian Empire which incorporated Finland, Latvia and Estonia, Protestants constituted some 3%.
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Canada was a Protestant majority country 1871-1961. This is confirmed by 9 consecutive censuses. 1941 census releaved at least 52% of the population claiming they were some kind of Protestant.