Year	Percent
1973	8.022
1974	18.76
1976	0.0476
1977	7.595
1978	7.739
1979	7.408
1980	0.594
1981	0.5027
1982	18.44
1983	29.53
1984	33.66
1985	23.06
1986	38.33
1987	19.49
1988	30.48
1989	11.62
1990	12.82
1991	21.58
1992	10.17
1993	13.6
1994	36.59
1995	22.89
1996	22.5
1997	17.39
1998	22.69
1999	11.97
2000	46.07
2001	6.534
2002	22.09
2003	29.46
2004	19.07
2005	16.01
2006	18.06
2007	24.49