What were the years of greatest economic decline between 1921 and 1939?

During the years 1921 and 1939, this was time when the Great Depression came. It was hard for the people to cope up because of the economic decline, the imports are very scarce compared to the ordinary days, the people have to survive and look for other possible means and ways just to survive. There was a great fundamental change in the economy.

Ineed it for the legislative branch test