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

The years of greatest economic decline between 1921 and 1939 were primarily during the Great Depression, which began with the Stock Market crash in late 1929 and lasted throughout the 1930s. The most severe impacts were felt in 1932, when unemployment soared and GDP plummeted. The economic situation began to improve gradually after 1933 with the implementation of New Deal policies in the United States, but the effects of the Depression lingered until the onset of World War II in the late 1930s.