At least half of the 400,000 prisoners registered in Auschwitz died (Prisoners of Auschwitz concentration camp). This figure can be arrived at by comparing the total of numbers assigned to prisoners with the figures for prisoners transferred to other camps (about 190,000), liberated (7,500), released (about 2,000) and escaped (at least 180). Extant documents that provide a basis for calculating mortality in the camp during specific periods are in particular the death books kept by the Germans.

(Mini dictionary of terms from the history of Auschwitz)