Spent a few minutes at FDLE website. My Central Florida county is small- we have (as of today) 347 REGISTERED sex offenders living in this county. I emphasize registered- how many are UNREGISTERED and unknown???
THAT is a big problem...
I know that if I were a sex offender, I wouldn't be inclined to register...
So probably the answer to your question is LOTS!
I heard on FNC, when Jessica Lunsford was missing, there are 500,000 known, nationwide.
I don't recall if those are registered or not.
They should be automatically be registered by a State, at time of parole.
Leaving it up to the parolee to register is just wrong thinking.
That is the BIG question. Because they're not closely monitored, a large number of 'em never bother to keep current with their registrations and what a crock registrations are --- BFD. They're still trolling the streets looking for prey. It's their nature.