Air raid casualties in Britain during the first five months of 1944 totaled 1,556 killed, with 2,916 seriously injured. During the five months of Operation Steinbock, the Luftwaffe lost about 330 bombers and crews. Thus, for every five people killed on the ground, the raiders lost one bomber and four trained crewmen killed or captured. On 12 June 1944, the first V-1 Flying Bomb attack was carried out on London. Approximately 10,000 V-1s were fired at London; 2,515 reached the city, killing about 6,184 people and injuring 17,981.