for 1959 through 2003, from the Census Bureau.
http://www.census.gov/hhes/www/poverty/histpov/hstpov13.htmlIn this chart, it becomes clear that "boom" years and recession years affect the chart the most. Mostly recession. From 1966 to present, the poverty rate hasnt' changed more than about 3%, and this includes several recessions and periods of economic growth.
Recessionary high points...
1993
1983
Years of relative "boom" have no large drop. This statistic might be explained by the following chart...
http://www.census.gov/hhes/www/poverty/histpov/hstpov1.htmlThese are the "definitions" of what is considered "poverty". I'm not sure what factors are involved, but there are some significant items to note that have a considerable effect on the statistical poverty.
For instance, the percent change in the "threshold" for poverty is relatively large for the years 1979 to 1982. I would assume this is because the relatively large inflation in the years 1977 to 1980 was "caught up with" by 1983. Unfortunately, the trend seems to apply on the previous end, as well, where poverty rates are unusually low during the mid-1970's, yet the economy was quite weak... It appears a lack of historical inflation skewed the numbers for the early part of the inflationary cycle lower, and the end of the inflationary cycle higher.
The raw number of families, for instance, considered to be in poverty was in a relatively steady trend downward from 1983 until the early 1990's.
Also, confirming the "inflation" skewing of hte numbers I'm theorizing, shows a really large drop in the raw number around 1997 to 2000. And, at the same time, the percentage change in the raw dollar threshold for those years is very, very small, in comparison to the historical trends.
Overall, it appears that times of negative economic growth cause a rise in poverty... and that inflation seems to impact our ability to define a threshold and thereby generate statistics.