Year	Percent
1970	96.34
1971	37.24
1975	1.035
1977	1.772
1978	2.946
1979	2.546
1980	0.3465
1981	3.795
1982	3.072
1983	1.697
1984	2.126
1985	2.421
1986	2.462
1987	2.069
1988	6.099
1989	2.622
1990	6.721
1991	1.782
1992	2.427
1993	7.658
1994	5.306
1995	2.28
1996	1.861
1997	1.058
1998	13.04
1999	8.829
2000	7.755
2001	20.55
2002	18.34
2003	16.17
2004	6.686
2005	1.375
2006	9.314
2007	4.154