After the dissolution of the Soviet Union (USSR) in December 1991, about 25 million ethnic Russians in post-Soviet states found themselves living outside the Russian Federation. All former Soviet citizens had a time window within which they could transfer their former Soviet citizenship to Russian citizenship. Where they did not exercise that choice, their resulting citizenship status outside Russia varied by state: from no perceivable change in status - as in Belarus - to becoming permanently resident "non-citizens" - as in Estonia and Latvia, which restricted citizenship to their pre-World War II citizens and their offspring (regardless of ethnic group) upon restoration of their independence in continuity with their sovereign identities prior to June 1940.