Year	Percent
1967	32.87
1968	29.68
1969	16.22
1970	20.96
1973	0.5833
1974	4.215
1975	2.192
1976	2.384
1977	1.939
1978	2.145
1979	4.22
1980	2.695
1981	0.8474
1982	3.144
1983	3.868
1984	4.195
1985	3.071
1986	2.323
1987	2.639
1988	3.303
1989	7.365
1990	3.883
1991	5.191
1992	1.089
1993	6.81
1994	3.143
1995	6.961
1996	7.664
1997	9.647
1998	11.18
1999	8.055
2000	2.007
2001	3.089
2002	4.222
2003	2.878
2004	6.086
2005	3.619
2006	5.889
2007	1.78