No one can prove the extent, but it's quite clear that Detroit's main focus in bookmaking. At least 90% of the arrests/indictments of Detroit members/associates have been for gambling-related offenses (including loansharking and extortion) over the last 20-30 years.

The organization as a whole is bringing in substantially less amounts of money than it did 15-20 years ago, much less 30-40 years ago. Their union influence, to the best of my knowledge, pretty much died off 15-20 years ago. But that doesn't say much, considering booking can generate enormous sums of money when done right.