Year	Years
1980	7.166
1981	6.682
1982	5.45
1983	3.604
1984	2.864
1985	2.031
1986	2.68
1987	2.945
1988	2.594
1989	2.551
1990	2.967
1991	2.84
1992	2.679
1993	2.865
1994	2.812
1995	3.054
1996	2.405
1997	1.656
1998	1.487
1999	1.679
2000	1.425
2001	2.242
2002	2.836
2003	2.36
2004	2.411