Long Depression
In the United States, the Long Depression began with the Panic of 1873. The National Bureau of Economic Research dates the contraction following the panic as lasting from October 1873 to March 1879. At 65 months, it is the longest-lasting contraction identified by the NBER, eclipsing the Great Depression's 43 months of contraction. Figures from Milton Friedman and Anna Schwartz show net national product increased 3 percent per year from 1869 to 1879 and real national product grew at 6.8 percent per year during that time frame. However, since between 1869 and 1879 the population of the United States increased by over 17.5 percent, per capita NNP growth was lower. Following the end of the episode in 1879, the U.S. economy would remain unstable, experiencing recessions for 114 of the 253 months until January 1901.
Great Depression
Many economists have argued that the sharp decline in international trade after 1930 helped to worsen the depression, especially for countries significantly dependent on foreign trade. In a 1995 survey of American economic historians, two-thirds agreed that the Smoot–Hawley Tariff Act at least worsened the Great Depression. Most historians and economists partly blame the American Smoot–Hawley Tariff Act (enacted June 17, 1930) for worsening the depression by seriously reducing international trade and causing retaliatory tariffs in other countries. While foreign trade was a small part of overall economic activity in the U.S. and was concentrated in a few businesses like farming, it was a much larger factor in many other countries. The average "ad valorem" rate of duties on dutiable imports for 1921–25 was 25.9% but under the new tariff it jumped to 50% during 1931–35. In dollar terms, American exports declined over the next four (4) years from about $5.2 billion in 1929 to $1.7 billion in 1933; so, not only did the physical volume of exports fall, but also the prices fell by about 1/3 as written. Hardest hit were farm commodities such as wheat, cotton, tobacco, and lumber.