Year	Percent
1969	5.255
1974	0.9314
1975	0.1862
1976	0.2382
1977	0.205
1978	0.8119
1979	1.425
1980	0.607
1981	4.147
1982	4.433
1983	0.7931
1984	1.594
1985	5.417
1986	1.283
1987	9.258
1988	7.792
1989	10.52
1990	15.44
1991	7.824
1992	10.29
1993	14.31
1994	14.79
1995	12.97
1996	10.65
1997	10.58
1998	12.04
1999	11.77
2000	18.17
2001	15.29
2002	13.54
2003	14.3
2004	15.24
2005	11.63
2006	19.94
2007	15.4