Keep in mind that that's true for almost the entire population in the 30s and 40s. Large quantities of the population had no better education than primary schoo

Keep in mind that that's true for almost the entire population in the 30s and 40s. Large quantities of the population had no better education than primary school plus job training. In the 1950s, only 5% of Germans had Abitur (which is 13 years of school and required for studying), in the 70s it was still only 10%. Most likely even less in the other countries (Hungary, Romania) where many of the garrison workers came from.