Online casino gambling has become a big business in the handful of states that allow it, but that growth spurt may be over.

In March, Rhode Island became just the seventh state to let residents bet on casino games like blackjack and roulette online. Just two more states, Florida and New Hampshire, are expected to follow over the next five years, according to Eilers & Krejcik Gaming LLC. By comparison, 38 states allow sports betting.

“US online casino expansion has been hard, and it’s getting a lot, lot harder,” said Chris Krafcik, a managing director at Eilers.