Year	Percent
1971	1.679
1975	6.823
1977	3.932
1978	3.15
1979	3.928
1980	0.9083
1981	1.042
1982	1.128
1983	1.436
1984	1.094
1985	4.049
1986	5.467
1987	2.215
1988	0.5614
1989	0.3606
1990	0.6354
1991	0.9086
1992	1.016
1993	0.419
1994	4.298
1995	1.36
1996	4.032
1997	3.8
1998	8.64
1999	16.85
2000	1.224
2001	4.338
2002	3.523
2003	11.31
2004	7.668
2005	5.582
2006	5.619
2007	12.97