Year	Percent
1967	14.57
1968	27.18
1969	17
1970	11.2
1973	2.027
1974	1.133
1975	1.717
1976	8.267
1977	4.236
1978	3.681
1979	3.414
1980	7.159
1981	2.148
1982	2.426
1983	15.98
1984	2.561
1985	2.693
1986	3.623
1987	1.547
1988	1.181
1989	0.302
1990	2.415
1991	1.237
1992	8.709
1993	4.924
1994	9.223
1995	9.016
1996	5.293
1997	7.653
1998	11.69
1999	5.322
2000	6.712
2001	5.825
2002	6.565
2003	12.26
2004	6.742
2005	9.889
2006	7.777
2007	2.37