Deflation
Deflation occurred periodically in the U.S. during the 19th century (the most important exception was during the Civil War). This deflation was at times caused by technological progress that created significant economic growth, but at other times it was triggered by financial crises — notably the Panic of 1837 which caused deflation through 1844, and the Panic of 1873 which triggered the Long Depression that lasted until 1879. These deflationary periods preceded the establishment of the U.S. Federal Reserve System and its active management of monetary matters. Episodes of deflation have been rare and brief since the Federal Reserve was created (a notable exception being the Great Depression) while U.S. economic progress has been unprecedented.
List of recessions in the United States
Major modern economic statistics, such as unemployment and GDP, were not compiled on a regular and standardized basis until after World War II. The average duration of the 11 recessions between 1945 and 2001 is 10 months, compared to 18 months for recessions between 1919 and 1945, and 22 months for recessions from 1854 to 1919. Because of the great changes in the economy over the centuries, it is difficult to compare the severity of modern recessions to early recessions. No recession of the post-World War II era has come anywhere near the depth of the Great Depression, which lasted from 1929 until 1941 and was caused by the 1929 crash of the stock market and other factors.