Using February 1, 2009 as our starting date, and March 31, 2013 as our end date, (the latest data from the FBI) Obama has been president for 1,520 days.
That equates to 36,480 hours, or 2,188,800 minutes.
Divide the 70,291,049 background checks by 2,188,800 minutes and you get approximately 32 checks for gun purchases every minute!