Year	Percent
1990	24.18
1991	26.67
1992	30.99
1993	41.63
1994	42.99
1995	41.41
1996	32.44
1997	30.07
1998	31.09
1999	37.95
2000	43.69
2001	38.14
2002	35.82
2003	34.4
2004	29.16
2005	31.8
2006	28.25
2007	31.35
2008	28.65
2009	34.36
2010	32.18