Question

Why has our tax rate gone up so much since the great depression?

Answer 1

If you mean since the 1930s, because of the enormous expansion of the size and cost of the Federal government.

http://www.usgovernmentspending.com/us_20th_century_chart.html

In 1930 the Federal governmetn spent 10 cents of every dollar spent in the United States. In 2010 the Federal government spent 40 cents of every dollar. That's the reason in a nutshell.