A dozen diocesan bishops will turn 75 this year, requiring them to submit resignations to the Pope. Among them are Cardinal Maida of Detroit and Cardinal McCarrick of Washington. That doesn’t mean they will definitely be retiring. Pope John Paul has had a habit in recent years of leaving men in office well after their official retirement date. Cardinal Bevilacqua didn’t actually get a replacement until he turned 80.
Ed Peter keeps an up-to-date list of bishops, their ages, and empty sees, although his list appears to only include the Latin rite. Right now, he lists 7 empty sees. So, not counting unexpected vacancies due to death or other reasons, about 20 dioceses could have new bishops this year, although it will liekly be a lot fewer than that.