According to the 1990 US Census, only 4,277 respondents claimed Belarusian ancestry; there are no reports as to the estimated population from the 2000 census. The precise number of Belarusian Americans is difficult to determine, as census and immigration statistics did not historically recognize Belarusians as a separate category, as the Belarus was for a time part of the Russian Empire and then the Soviet Union when early immigrants arrived. Many of them were recorded as Russian or Polish, depending on the region of Belarus where they were born.