Filippo Altissimo and Giovanni L. Violante, "Persistence and Nonlinearity in US GNP and Unemployment", Journal of Applied Econometrics, Vol. 16, No. 4, 2001, pp. 461-486. The data are the US GNP at 1982 prices and the US total unemployment rate in percentage points from the Citibase database, 1993 release (the database acronyms are respectively: USGNP82 and LHURN). The data frequency is quarterly ranging from 1951.4 to 1990.4, for a total of 157 observations. The quarterly total unemployment rate is recovered as simple average of the monthly figures, while the US GNP is already quarterly. All data are in the file av-data.dat, which is a plain ASCII file in DOS format. In the data file, the first column is the US GNP and the second one the total unemployment rate. In the estimation step of the work, the US GNP is first log transformed and then first differenced, while the unemployment rate is only first differenced. Finally, the log changes of US GNP are multiplied by one hundred, such that both variables are expressed as percentage changes.