From what I can find Germany seemed to have the highest or one of the highest unemployment rates during the worldwide economic depression in the 30's.
Explanation:
I'm am unsure about exact dates, but in the U.S. during the Great Depression 25% of people were unemployed. In Great Britain the unemployment rate seems to vary depending on the source , but it seems to be around 15-22%. In Germany the unemployment rate during the early 30's was 1/3 or 33.3%.
