Year	Percent
1967	44.68
1968	66.1
1969	7.082
1970	32.29
1971	45.74
1972	13.4
1973	36.83
1974	58.9
1975	46.88
1976	48.39
1977	50.17
1978	43.14
1979	51.57
1980	74.32
1981	47.09
1982	42.6
1983	42.05
1984	34.26
1985	33.67
1986	27.4
1987	41.67
1988	25.36
1989	29.19
1990	36.32
1991	30.59
1992	28.07
1993	18.78
1994	20.65
1995	18.69
1996	15.23
1997	16.25
1998	12.56
1999	7.242
2000	5.327
2001	8.507
2002	5.349
2003	5.679
2004	5.543
2005	8.967
2006	10.89
2007	12.45