Year	Percent
1973	9.42
1974	4.026
1975	2.421
1976	2.341
1977	1.945
1978	0.4
1979	3.933
1980	1.308
1981	0.08085
1983	0.279
1984	0.5937
1985	0.4935
1987	15.4
1988	0.1733
1989	0.3298
1990	0.2452
1991	0.5287
1992	5.596
1993	3.727
1994	6.348
1995	9.965
1996	6.176
1997	10.45
1998	10.3
1999	11.22
2000	5.309
2001	34.45
2002	17.41
2003	20.26
2004	14.54
2005	18.34
2006	16.37
2007	25.76