I've did 3 boxes of dimes so far and got 2 keepers (1947p, 1963p)
2 boxes of half dollars, 7 keepers total, 1x 90%, 6x 40%... (All from box 1)
Half dollar box #2 was a SKUNK
The percentage of silver in halves, would be the highest. Although I don't do near the quantity everyone else here does. I don't order boxes, I just take what the tellers keep for me.
Dimes are a higher percentage than quarters for me. I think part of that is because of the size of the dime makes it easy to not notice and i think part of it is because we were buried by State quarters for over 10 years. JMO.