Year	Percent
1967	7.856
1968	15.65
1969	8.359
1970	11.29
1973	0.8583
1974	1.636
1975	4.382
1976	3.65
1977	1.068
1978	0.9601
1979	1.383
1980	2.129
1981	2.129
1982	2.095
1983	2.754
1984	1.557
1985	3.025
1986	2.936
1987	2.717
1988	3.324
1989	2.989
1990	4.758
1991	4.435
1992	4.273
1993	4.163
1994	8.453
1995	7.388
1996	6.055
1997	7.768
1998	6.907
1999	7.434
2000	6.927
2001	5.243
2002	6.97
2003	5.673
2004	5.853
2005	4.495
2006	4.326
2007	3.872