Year	Percent
1985	22.09441
1986	22.4749
1987	19.59428
1988	20.2984
1989	23.94986
1990	24.15029
1991	21.77017
1992	17.35328
1993	18.10057
1994	17.93575
1995	18.10622
1996	25.54595
1997	28.57415
1998	26.4607
1999	32.24143
2000	38.57071
2001	31.80156
2002	30.83111
2003	28.19097
2004	35.97242
2005	38.50288
2006	38.52825
2007	35.91177