"In 1931 in the Soviet Union lived 81 million Ukrainians and only 77 million Russians ... Next census in 1937 indicates that were 26 million Ukrainians in the Soviet Union , ...".
Source: http://nebo.at.ua/publ/istorija/85_rokiv_tomu_ukrajinciv_u_srsr_bulo_bilshe_nizh_rosijan/10-1-0-161 (in Ukrainian)