Year	Years
1980	2.452
1981	1.642
1982	0.8066
1983	1.439
1984	2.365
1985	2.919
1986	2.365
1987	2.506
1988	2.502
1989	3.138
1990	3.497
1991	4.001
1992	4.41
1993	4.048
1994	4.264
1995	3.296
1996	3.104
1997	3.124
1998	2.9
1999	2.796
2000	3.443
2001	3.136
2002	3.223
2003	3.244