According to new data from IHS Screen Digest, Apple remained in the top spot in the U.S. market for movie electronic sell through (EST) and Internet video on demand (iVOD) in 2010, despite rising market share for competitors. iSuppli reports that the iTunes Store accounted for more than two-thirds—64.5 percent—of the EST/iVOD market in 2010, down from 74.4 percent in 2009; in the EST market alone, Apple accounted for three quarters…