This is just the start of research, but apparently Sicilian mob extracts 1.6B euro from the island with 80% of businesses paying, and the GDP is about 90B. So those businesses are perhaps losing 2.5% although the article makes it seem like they tend to be small or individual businesses that pay, which would increase that. Obviously very rough and I’d like to know more.

https://en.m.wikipedia.org/wiki/Pizzo_(mafia)