The Mafia is a pyramid scheme. The street guy--whether he's made or is an associate--does all the work. There is no set percentage. It all depends on the boss's greed. As you saw in "Goodfellas," Henry, as an unmade guy, kicked a set amount--$60k--to Paulie from the Air France heist. And in "Sopranos," right after Chris got made, Paulie Walnuts, his boss, gave him a "living" and demanded $4k/week from it. In those case, I'm guessing, each Paulie kept some for himself and kicked a lesser amount upstairs to his own boss. How much less? That'd depend on his boss's greed and what each Paulie thought he could get away with. But then again, each Paulie's boss had multiple people below him kicking money upstairs to him.

I think both those examples are broadly accurate--the difference is that a made guy gets a living and has to kick back a regular percentage or amount to his boss, while the associate kicks back on individual jobs done under family auspices.

As for "Blue Comet," I think the reference was that the family had too many bosses who brought in no money by themselves but had to be paid off by the workin' stiffs. So, the estimate was that 50 percent of all the money earned by the worker-bees was bled off by the bosses. I don't know if that's a lot or a little because every boss sets his own fee.