[FortunaMaximus]

"15 years old and up"

That's a hell of a lot of 98 pound "weaklings" on the early end of that scale AND the late end of that scale. Less than 98, actually, if you account for Asian and African males.

If OP had asked for the "average weight of the average Terran male"?

I'd probably have suggested something like 150-160.

Edit: Population growth also accounts for the imbalance of the age distribution across the scale.