Year	Percent
1967	40.25
1968	31.58
1969	16.59
1970	17.82
1971	8.731
1972	10.99
1973	16.68
1975	5.388
1976	12.2
1978	24.26
1979	24.83
1980	6.773
1981	11.59
1982	9.632
1983	7.532
1984	8.621
1985	11.51
1986	10.43
1987	11.66
1988	7.204
1989	10.96
1990	14.25
1991	14.21
1992	14.21
1993	14.21
1994	29.48
1995	15.96
1996	15.98
1997	24.39
1998	13.11
1999	22.79
2000	20.26
2001	6.053
2002	8.183
2003	3.918
2004	25.76
2005	14.49
2006	19.33
2007	16.77