In May 2007, YouTube launched its Partner Program, a system based on AdSense which allows the uploader of the video to share the revenue produced by advertising on the site. YouTube typically takes 45 percent of the advertising revenue from videos in the Partner Program, with 55 percent going to the uploader. There are over a million members of the YouTube Partner Program. According to TubeMogul, in 2013 a pre-roll advertisement on YouTube (one that is shown before the video starts) cost advertisers on average $7.60 per 1000 views. Usually no more than half of eligible videos have a pre-roll advertisement, due to a lack of interested advertisers. Assuming pre-roll advertisements on half of videos, a YouTube partner would earn 0.5 X $7.60 X 55% = $2.09 per 1000 views in 2013.