Real GDP Fell by 29.3% From 1930 to 1933

The chart above displays annual real GDP growth from 1928-1945 (data here), showing the -29.3% cumulative drop in real GDP between 1930 and 1933 during the Great Depression. That would be like today's real GDP going from the current level of $14.5 trillion back to the level of real output in 1996. And that seems highly unlikely.