I'm not sure how many, but I think I read something about the FBI, or maybe the CIA, having several agents in the Sacramento area specializing in this group alone.
Russians come from Russia, Belarus and Ukraine, with the exception of the formerly exhiled, living as minority groups in places such as Azerbaijan, Georgia, and a few other places in Europe.
I disagree, most of those Slavs here for better life and not for persecution.
True, they were persecuted until Perestroika and Gorbachev but not since 1980's.
If there is any real problem with the data the FBI provides it is that they categorize anyone from any of the republics of former Soviet Union as Russian. I'm a second generation Russian-American and as soon as people figure out my last name is Russian they invariably have to tell me some story about Russian criminals.
When I was dating a Russian I had people constantly telling me she was trouble waiting to happen.