"Until the 1970s, high inflation usually went hand in hand with high employment and output.In the United States, inflation tended to increase when investment was brisk and jobs were plentiful. Periods of deflation or declining inflation [...] were times of high unemployment of labor and capital. But a more careful examination of the historical record has revealed an interesting fact: The positive association between output and inflation appears to be only a temporary relationship. Over the longer run, there seems to be an inverse-U-shaped relationship between inflation and output growth."