"The Smoot-Hawley tariffs came in June 1930. There is wide academic consensus that these prolonged the Great Depression, they certainly reduced global trade"
"Unemployment was at 7.8% in 1930 when the Smoot-Hawley tariff was passed, but it jumped to 16.3% in 1931, 24.9% in 1932, and 25.1% in 1933.[12]" http://en.wikipedia.org/wiki/Smoot-Hawley_Tariff_Act
