U.S. retail operating systems boxed software revenue increased 35 percent in 2009, but it was not enough to lift non-games software into positive territory, according to new research from The NPD Group. Total retail non-games software revenue fell 7 percent in 2009 to $2.4 billion. That is an improvement over the 10 percent decrease in 2008. Unit volume for 2009 dropped 6 percent and average selling price dipped 2 percent.