Earlier this year, so my PO told me.

I once bought books 1-11, 3 of which were TPBs, of 'The Wheel of Time' and they were sent in a 3kg satchel. The TPBs go well over 500g each, and the MMPBs go close to 500g each. And, yes, it was a squeeze (apparently a bit of judicious heat will stretch the plastic without tearing it).