By 1935 the proportion of women workers in the ussr’s workforce was  twoonefourthree  in every five.

Two in every five.

In the 1920s, the percentage of women in the USSR's workforce was about 1 in 4 -- remaining around 28% through most of that decade.  But those numbers would increase under the First and Second Five-Year Plans instituted by Joseph Stalin.  By 1935, the percentage of women employed in large-scale industry in the Soviet Union had grown to 40%  (representing two out of every five workers).  

For further information and detail, you might consult the book, The Position of Women in the USSR, by G.N. Serebrennikov (published 1937).

The answer is two in every 5. In 1935 women made up a total percentage of 44% of the work force of the USSR, and by the year 1937, it rose to 50%. Addition to factory work, many women in the USSR worked in healthcare and education.