Despite feeble challenges from Get Him to the Greek and Killers, Shrek Forever After held the top spot at this weekend's box office for the third week in a row. The green ogre and friends pulled in an additional $25.3 million in the U.S. and Canada this weekend—resulting in an $183 million box office overall. Greek, the Russell Brand and Jonah Hill comedy, came in second with $17.4 million on its opening weekend, and Killers, which stars Ashton Kutcher and Katherine Heigl, raked in $16.1 million. The weekend was a somber reminder of the year-long decline of ticket sales, as overall sales were down 24 percent from a year ago. This same weekend last year, The Hangover pulled in $45 million.