Why did he rank Catania only 4? I would put Catania just under Palermo and Trapani , i guess he gave that rank somewhere in the late 80s or early 90s when it was under Santapaola's, when they were the most powerful. I guess today that rank would be higher because of 'Ndrangheta and drug trafficking going on there.
Probably it was an even earlier period he was referring to, the late 70s or first 80s, since he started collaborating with Falcone in 1984.