Criminal "protection" "taxes" were common 15 years ago and even then it was nothing like "20%" for everybody, it varied greatly from place to place and from business to business and depended on who you know and where are you from.
Small-to-medium businesses are free from anything like that by now AFAIK.
To conduct a "serious" business in most fields you still have to know the right people though, if you don't want it to be taken from you.
Not everybody, I was talking about people operating large enterprises. When you talk about knowing the right people, I think you are describing this 'tax.'
As to variance: it was my understanding that the FSB was much more even in its pricing than the chaos and gangs before it.
Most big companies I know just hire a right person who knows a few FSB generals and create their very own "defense" departments to solve these problems. They pay only salaries to people who know what to do. No bribes or "taxes" whatsoever.
Small-to-medium businesses are free from anything like that by now AFAIK.
To conduct a "serious" business in most fields you still have to know the right people though, if you don't want it to be taken from you.