A new report from the NPD Group has found that nearly half of U.S. kids download music from iTunes. The group estimates that up to 70% of U.S. kids aged 9-14 download music in a given month, with 49% using iTunes. Another 26% use Limewire, while an estimated 16% download music from MySpace. The NPD Group blames parents who let their children use the web unsupervised for the high percentage of illegal downloads. “The music industry hoped that…