sentences:  Reviewing 600 photoreconnaissance images, Butt did a statistical analysis of the attacks completed in June and July 1941.The resultant Butt Report showed that Bomber Command was having great difficulty delivering its bombs over its targets, with only 5% of bombers setting out bombed within of the target.This report was a key impetus to the formation of Bomber Command's Pathfinder Force, which greatly improved the accuracy and destructive power of Bomber Command.