Year	Percent
1990	2.388
1991	2.115
1992	2.853
1993	4.393
1994	7.125
1995	8.951
1996	9.258
1997	11.49
1998	13.21
1999	14.98
2000	15.53
2001	13.93
2002	15.73
2003	14.21
2004	13.5
2005	13.99
2006	13.6
2007	12.52
2008	12.64
2009	12.67
2010	12.92
