There wasn't a single year with 90K gun related deaths, especially not in 2012, they might have had numbers for total "gun related casualties" which includes injuries, homicides, suicides and accidental discharges which might be closer to the actual figures. These are the FBI figures https://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2012/... so shy under 9K crime related gun death.

With all honesty that figure should've made any sensible person give it the sniff test even if it was released by the NRA yet alone by the Brady Campaign. So either the total report is BS, the figures weren't for fatalities but for all casualties or your memory isn't as good as you think it is or any combination of all of the above.