Year	Years
1980	4.034
1981	4.104
1982	3.529
1983	2.946
1984	2.995
1985	2.819
1986	2.677
1987	2.431
1988	2.737
1989	1.937
1990	1.723
1991	0.2685
1992	-0.0504
1993	0.3676
1994	-0.07156
1995	-0.02177
1996	-0.1793
1997	-0.1546
1998	0.07034
1999	0.4711
2000	1.216
2001	2.854
2002	3.318
2003	3.154
2004	3.786