Year Years 1980 4.811 1981 3.14 1982 1.228 1983 0.6366 1984 0.3688 1985 0.03164 1986 -0.3906 1987 -0.7445 1988 -0.6445 1989 -0.4491 1990 -0.5575 1991 0.2452 1992 1.442 1993 1.436 1994 1.43 1995 1.523 1996 1.715 1997 2.163 1998 2.316 1999 2.815 2000 3.858 2001 4.184 2002 4.147 2003 4.158 2004 4.28