Year Years 1980 2.391 1981 1.159 1982 1.4 1983 0.7958 1984 0.5406 1985 0.78 1986 0.7474 1987 0.2772 1988 0.08939 1989 0.331 1990 -1.675 1991 -0.9545 1992 -1.772 1993 -1.244 1994 -2.218 1995 -2.073 1996 -1.6 1997 -1.178 1998 -0.7757 1999 -0.922 2000 1.059 2001 2.095 2002 2.781 2003 2.996