How much ammunition (in addition to those 90 million firearms) has been bought by private citizens since November 2008?
A lot.
I dunno, but I got 5,8854 rounds of 5.56x45, 1,800 rounds 9mm, 675 rounds of assorted .12 GA (buckshot and slug) 2200 of .22 LR and 555 rounds of .300 Blackout of it for myself with enough magazines and stripper clips for reloads. I can equip a fire team by myself.