Year	Percent
1967	50.58
1968	6.142
1969	21.2
1970	50.63
1972	4.507
1973	0.0959
1974	0.2489
1975	3.117
1976	1.226
1977	1.46
1978	3.257
1979	0.8711
1980	0.34
1981	2.579
1982	1.389
1983	6.27
1984	0.9927
1985	1.785
1986	3.455
1987	3.651
1988	1.236
1989	4.487
1990	2.551
1991	5.587
1992	9.46
1993	9.089
1994	10.47
1995	7.6
1996	4.391
1997	16.05
1998	7.48
1999	13.25
2000	12.4
2001	10.85
2002	11.44
2003	12.48
2004	11.12
2005	6.27
2006	6.298
2007	5.739