This is hard considering the scarcity of heavy-arse dumbbells not to mention a significant amount of arm/shoulder strength required which isn't so for the back squat. An easier comparision can probably be made with the zercher as steve mention or to a less extent the front squat.
Looking back through my log, the best goblet squat I did was 19x120, the heavy dumbbell available. Best squat around that time was a 1x395 and 12x315. Hard to compare those numbers, but...