Year	Years
1980	0.4092
1981	0.5913
1982	0.6816
1983	3.488
1984	3.326
1985	4.409
1986	5.963
1987	5.228
1988	7.426
1989	6.613
1990	7.204
1991	7.323
1992	7.094
1993	5.424
1994	5.819
1995	4.835
1996	4.673
1997	5.13
1998	3.491
1999	3.479
2000	2.683
2001	2.948
2002	3.196
2003	2.803