Year	Percent
1974	9.331
1975	0.2793
1980	2.874
1986	2.412
1988	2.85
1989	2.591
1990	14.12
1991	22.23
1992	4.779
1993	24.64
1994	7.118
1995	51.27
1996	15.72
1997	30.95
1998	18.98
1999	15.12
2000	25.54
2001	29.56
2002	12
2003	21.01
2004	16.85
2005	22.85
2006	20.72
2007	15.54