Year	Percent
1967	3.334
1969	3.082
1970	1.47
1973	0.4817
1974	2.006
1975	0.2529
1976	0.8095
1977	0.3012
1978	3.223
1979	1.715
1980	2.05
1981	0.4428
1982	0.6747
1983	4.29
1984	5.415
1985	3.243
1986	4.32
1987	2.896
1988	3.973
1989	4.95
1990	9.155
1991	2.448
1992	5.62
1993	7.248
1994	3.065
1995	2.546
1996	1.229
1997	1.616
1998	1.162
1999	1.503
2000	1.582
2001	2.311
2002	2.883
2003	2.461
2004	2.2
2005	1.858
2006	1.965
2007	2.311