Rear end ride height

I have a stock '01 F250 4x4 excab SB with the 265/75/16 tires on the stock alloy rims. I was wondering what height the rear end of some of the others sit? It looks to me like my rear is sagging just a bit, I have a cross body tool box, but not a lot of weight in it. I figure a 3/4 ton would take a bit to start to droop. I was going to measure from the ground to the fender well lips, then to the bottom or top edge of the bumper. Anyone willing to measure theirs and post the results? Any suggestions on where to measure? Thanks