Hard to say exactly what takes precedent. I bet the gambling, because its a lot safer and a lot of guys are willing to work within that sector while drugs are good until everyone gets caught then theyre fucked for a decade or more even though the money is probably much bigger during its course.
Construction is big still and the amount of juice loans on the streets is just huge. Even if you just consider the amount of money the Todaros can loan out youd be talking about millions and millions.