An example of the difficulties of precision bombing was a raid in the Northern Hemisphere summer of 1944 by 47 B-29's on Japan's Yawata Steel Works from bases in China. Only one plane actually hit the target area, and only with one of its bombs. This single general-purpose bomb represented one quarter of one percent of the 376 bombs dropped over Yawata on that mission. It took 108 B-17 bombers, crewed by 1,080 airmen, dropping 648 bombs to guarantee a 96 percent chance of getting just two hits inside a 400 x German power-generation plant.