The Soviet Union was still ruled by Russians [0]… “ From 1919 until 1991, 89 members of the Politburo were Russians (which makes up 68 percent). In distant second were Ukrainians, who had 11 members in the Politburo, making up 8 percent. In third place are both ethnic Jews and Georgians, who had 4 members respectively.”
It was less than the population since by population , 80% are Russian [1], but still shows that the USSR was ruled by Russians.
[0] https://en.wikipedia.org/wiki/Politburo_of_the_Communist_Par...