the good thing about the art on old pinballs is its done very simular to what you saw in comic books of the era they come from.
thats what i have noticed and hotgirls are very common in comics and it all looks very simular to me. its very cool popart style on pins and almost cliche so i would take a guess and say more pinballs would have hotgirls on them than there are pinballs with out girls on them. only two of the 6 machines i have had didnt have girl with perky tits on it somewhere. lol maybe more modern games are loosing the hotgirl with big tits thing to be more political correct???