The 1922 census of the Communist Party showed less than 1,000 Jews, according to historian Richard Pipes (father of Daniel Pipes) and other sources. Two heavily Jewish political parties were the only parties in the Russian legislature to condemn the Bolshevik power grab.
The Bolsheviks in the beginning were an infenitesima bunch. 1000 Jews is a large percentage. They were decision makers. They held key positions in the party and NKVD. Of course, they were almost all slaughtered in the end. But they played a pivotal part in messing up Russia. The Russians still hold the grudge.