The following numbers are the figures for the prime rate of interest over two cycles: 1975–1980 and 1983–1990. Just to make the calculations easy, assume that the years represent an entire business cycle (the first trough actually occurred in the first quarter of 1975 and in the third quarter of 1980, while the second cycle went from the last quarter of 1982 to the first quarter of 1991). Find the average prime rate for the two different business cycles.