The consumer price index was 53.8 in 1975, 82.4 in 1980, 107.6 in 1985, 130.7 in 1990, 152.4 in 1995 and 172.2 in 2000 (1982-84 = 100). during which five-year interval was the annual inflation rate the highest? during which interval was the average annual inflation rate the lowest? what was the trend in inflation over the last quarter of the twentieth century? hint: the inflation rate is the annual percentage change in the price index.)