Silver Versus Copper Errors

My question is generally about the rarity of errors (off center, broadstruck, for example) on older dimes versus older copper coins.

I've noticed that errors on Barber and Mercury dimes are significantly rarer than errors on wheat cents or even later Indian cents. My observation is partly based on how rarely I see the errors on the dimes, but also that the selling prices of off center dimes seems to be much more than those on Wheat cents from the same year, or even some of the later Indian cents.

Is this due to the lower mintages of the Barber dimes or are errors on Silver coins just less likely to happen for some reason than copper cents?