Leading online radio service, Oakland, Calif.\'s Pandora, said it is dropping its limits on free mobile listening starting in September. Currently, Pandora listeners who use the service for free can only listen to Pandora stations for 40 hours per month, Pandora said in a release Thursday. But that will change starting Sept. 1, the company said. \"We\'re pleased to once again maximize free listening for everyone on Pandora,\" said Tim Westergren, Pandora\'s founder. \"The more than 70 million listeners that tune in every month will now have more time to hear the music they love, and thousands of working artists will reach more fans.\" The cap on how much music free users could listen to was instituted in February in an effort to curb the royalty costs Pandora pays, Billboard.com reported. However, the listening limits caused a 12 percent drop in listener hours. The cap did bring Pandora\'s royalty fees to 52 percent in the second quarter, down from 59.8 percent the year before. Pandora has also put a new limit on the number of songs free users can skip; previously, free users could make six skips per station per hour, but now they are limited to 12 skips in a rolling 24-hour period. The company has also introduced a \"sleep timer\" that shut Pandora off for mobile users after a predetermined period of time.