Year	Percent
1967	40.43
1968	33
1969	22.95
1970	23.89
1972	20.9
1973	5.522
1974	6.701
1976	1.786
1977	1.572
1978	12.43
1979	1.826
1980	3.338
1981	1.768
1982	5.7
1983	3.574
1984	6.577
1985	4.645
1986	5.527
1987	6.253
1988	4.658
1989	3.494
1990	4.473
1991	4.923
1992	6.979
1993	17.46
1994	10.47
1995	7.632
1996	3.309
1998	2.497
1999	0.2102
2000	0.498
2001	0.5078
2002	0.5254
2003	2.537
2004	1.334
2005	2.233
2006	1.726
2007	1.934