Today, it's generally understood to be something like 11 million total, of which 6 million were Jewish. Have these figures always been the universally agreed upon numbers? How have they changed? Were they different from country to country?
The amount of known Jewish deaths known increased over time as better research became available. In the 1950's, estimates ranged around 4-4.5 million Jewish deaths. In the early 1960's, Raul Hilberg (USA) estimated 5.1 million Jews murdered, which is generally considered a "conservative estimate". Other less well known historians reached higher figures around the same time. Wolfgang Benz, from Germany, furthered the research of Hilberg and others into the 1990's and made a wide ranging estimate of 5.3-6.2 million Jewish victims.