Year	Percent
1969	1.136
1970	3.882
1972	0.8179
1973	4.142
1974	7.924
1975	39.33
1976	14.2
1977	9.941
1978	1.906
1979	2.77
1980	8.634
1981	16.84
1982	2.771
1983	2.481
1984	30.38
1985	16.31
1986	14.59
1987	24.73
1988	11.49
1989	15.41
1990	6.13
1991	20.63
1992	8.753
1993	7.808
1994	3.021
1995	7.097
1996	17.49
1998	13.45
1999	15.08
2000	11.2
2001	12.59
2002	16.86
2003	14.34
2004	14.61
2005	13.15
2006	12.86
2007	14.51