I asked my students 11 of the questions she asked. Over 80% knew the answers. These were 9-12 graders living in a Rural district in Virginia. all of them knew what the Holocaust was and where it began The vast majority knew that it was not just Jewish people that were killed, but some of them left out 1-2 groups in their list. Only one did not know that Germany was in France, but did know about D-Day (His Grandfather was one of the participants.)
Our district does teach it from 8th grade on.