It sadly doesn't go back further than the 1960s. If you select Western Europe, the number seems to be falling (back from almost 100kg, though). USA, not so much.
Note though that for what your parent describes, you'd want numbers to go even further back, then you could likely see the whole effect of post-WW2 boom; though WW2 itself would obviously also extremely skew the data in the 40s.
It sadly doesn't go back further than the 1960s. If you select Western Europe, the number seems to be falling (back from almost 100kg, though). USA, not so much.
Note though that for what your parent describes, you'd want numbers to go even further back, then you could likely see the whole effect of post-WW2 boom; though WW2 itself would obviously also extremely skew the data in the 40s.