Percent change in the CPI for transportation minus the percent change in the CPI research series for transportation, 1978-98 CPI-U CPI-U-RS Difference 7.7 7.5 1978 0.2 18.3 18.5 1979 -0.2 14.6 15.6 1980 -1.0 10.9 10.5 1981 0.4 1.8 2.0 1982 -0.2 3.9 4.2 1983 -0.3 3.1 2.7 1984 0.4 2.6 2.8 1985 -0.2 -5.9 -6.2 1986 0.3 6.1 5.9 1987 0.2 3.0 2.5 1988 0.5 4.0 3.7 1989 0.3 10.4 10.6 1990 -0.2 -1.5 -1.5 1991 0.0 3.0 3.2 1992 -0.2 2.4 2.4 1993 0.0 3.8 4.4 1994 -0.6 1.5 1.3 1995 0.2 4.4 4.7 1996 -0.3 -1.4 -1.5 1997 0.1 -1.7 -1.7 1998 0.0