Peter Lindert and Jeffrey Williamson write:
The new estimates imply that America’s real income per capita dropped by about 22% over the quarter century 1774-1800, a decline almost as steep as during the Great Depression between 1929 and 1933, and certainly longer. If the 1790s recorded brisk growth rates (Sylla 2011: pp. 81-3), it follows that the Revolutionary War period could have been America’s greatest income slump ever. That fall may have been 28% or even higher in per-capita terms.
Factors behind this decline include the Revolutionary War, the lagging South, and a negative trade effect. The article is interesting throughout, for instance:
In 1774 the colonial South had about twice the per-capita income of New England, even when one rightly counts slaves as in the population. The absolute economic decline of the South Atlantic over the last quarter of the 18th century and its relative decline over the subsequent four decades stand out as an example of what has come to be called reversal of fortune (Acemoglu et al. 2002). By 1840 the South Atlantic was well behind the Northeast, having been well ahead in 1774, and its population share of the original thirteen colonies had fallen too. Furthermore, we can find no evidence that the colonial South had any large army of poor whites in 1774; indeed, Southern free labour had some of the highest wages anywhere in the colonies. Thus, it appears that the ubiquity of poor whites in the South was strictly a nineteenth-century phenomenon, associated, presumably, with post-1774 decades of very poor growth. Why the reversal of fortune for the South? We are still not sure whether it was bad luck in its export commodity markets, institutional failure, or exceptionally severe wartime damage.