Up to the end of March 1945 there had been a total of 314 air raids on Berlin, with 85 of those coming in the last twelve months Half of all houses were damaged and around a third uninhabitable, as much as 16 km² of the city was simply rubble. Estimates of the total number of dead in Berlin from air raids range from 20,000 to 50,000; current German studies suggest that a figure in the lower part of this range is more likely. This compares to death tolls of between 25,000 and 35,000 in the single attack on Dresden on 14 February 1945, and the 42,000 killed at Hamburg in a single raid in 1943, with both the Hamburg and Dresden raids each having lower casualty totals than the 9/10 March 1945 "Operation Meetinghouse" single firebombing raid on Tokyo, devastating some 15.8 square miles (40.9 km²) causing the loss of at least 100,000 lives in the Japanese capital. The relatively low casualty figure in Berlin is partly the result of the city's distance from airfields in Britain, which made large raids difficult before the liberation of France in late 1944, but also due to the city's superior air defences and shelters.