More recently, there have been more -F accidents than Pax version accidents. True and because of two reasons:
1: more Frtr versions flying now than Pax versions
2: smoke/fire and cargo shift issues due to loading and lithium batteries
Check the actual numbers for yourself here. Pax hull losses more than double freighters (including acts of terrorism of course)
Your 90-10 % ratio is off by a two times margin. Out of 1556 747s built, 311 were freighters which equals 20%. This doesn't include the BCF conversions of which many are still in service (can't find an exact number of airframes converted) not does it include all the combi/special versions built.
https://en.m.wikipedia.org/wiki/Boeing_747_hull_losses