Here’s a few stats for the USA so far this year:
1 Succeeded (Coadjutor -> Ordinary)
2 Ordinaries (includes the 1 in September)
So obviously the majority of new bishops were existing bishops that were moved.
Here’s the overall view:
Currently Vacant: 10
Ordinaries Over 75: 12
Auxiliaries Over 75: 2
(and those reaching the retirement age in the next year: 6 Ordinaries)
So essentially the USA needs 22 bishops right now and another 6 in the next year (not counting auxiliaries).