Year	Percent
1973	20.1
1974	5.142
1975	8.175
1976	11.63
1977	17.08
1978	2.653
1979	15.5
1980	20.46
1981	29.11
1982	3.959
1983	3.539
1984	5.124
1985	0.8992
1987	7.037
1988	0.6133
1989	10.19
1990	8.002
1991	17.12
1992	23.75
1993	13.16
1994	7.807
1995	15.64
1996	25.73
1997	4.288
1998	2.106
1999	17.93
2000	3.384
2001	7.133
2002	8.76
2003	11.97
2004	10.75
2005	7.253
2006	14.18
2007	8.194