Year	Percent
1990	7.62
1991	10.24
1992	20.11
1993	25.94
1994	28.96
1995	30.78
1996	36.89
1997	39.86
1998	43.2
1999	34.55
2000	38.73
2001	39.14
2002	38.21
2003	38.13
2004	40.08
2005	39.74
2006	38.69
2007	37.7
2008	36.7
2009	53.37
2010	51.35