Roger Waters' "The Wall" tour is the top ticket seller of the first half of 2012 according to the trade magazine PollStar. Waters' road rendition of the Pink Floyd rock opera has sold $158.1 million in worldwide ticket sales so far this year, ahead of Bruce Springsteen with $79.9 million. Interestingly, Waters ranked second in North America at $61.9 million, with Cirque du Soleil's Michael Jackson: The Immortal show topping the domestic list at $78.5 million. The mag predicts that Waters' will not necessarily be in the lead at the end of the year, however; Madonna has $42 million worth of tickets so far this year and doesn't hit North America until next month, while Springsteen also has a significant number of dates still left to play. PollStar reports that ticket sales were up 1.2 percent during the first six months, with 18.6 million tickets sold for a $1.1 billion tally.