A couple of interesting stats.. It has done extremely well overseas:
International hit MIB 3 raked in another $19.7 million this weekend from 79 markets, which brings its foreign total to $391.6 million. It's now a few days away from passing Hancock ($396.4 million) to become Will Smith's second-highest grossing movie ever overseas behind Independence Day ($511.2 million).
If you look at US attendance it was well down... Adjusted for Ticket Price Inflation
Rank Title Adjusted Gross Unadjusted Gross Release
1 Men in Black $432,564,100 $250,690,539 7/2/97
2 Men in Black II $259,572,600 $190,418,803 7/3/02
3 MIB 3 $152,679,000 $152,679,000 5/25/12