Year	Years
1980	2.626
1981	2.261
1982	1.774
1983	1.584
1984	1.895
1985	2.141
1986	1.911
1987	1.729
1988	1.73
1989	1.594
1990	1.943
1991	2.394
1992	2.656
1993	2.299
1994	2.26
1995	2.232
1996	2.023
1997	2.047
1998	1.918
1999	1.801
2000	1.65
2001	1.356
2002	1.171
2003	1.287
2004	1.247