I don't know what the ratio is but the dimes I find in pennies get tossed into a separate box. When I have enough dimes I go to the LCS and purchase as much silver as I can. This year (so far) I have bought 2 one ounce silver rounds and 4 pre 64 dimes. It's like finding silver in cent rolls! By the way, you'll get more dimes from cent bags that pop off the coin counters than rolled.