Most deer, unless extra beefy (muscular) or real skinny, will yield about 45% of the live weight or 57% of the field dressed weight back to boneless edible venison. If you get alot more than that it isn't trimmed well....if you get alot less than that then you probably had bullet damaged meat or it was trimmed a little too well. Deer that are REALLY small actually wil yeild a higher percentage of meat back (up to 67% of field dressed weight), but even really big deer rarely give back more than 56% of the field dressed weight.
I'm basing that on years of butchering my own deer and comparing that to the yeild I've seen after watching others butcher deer. And I base my live weight/ dressed weight on chest girth measurement. I've only actually weighed a few deer. The chest girth method is pretty accurate.