Year	Percent
1992	10.76051
1993	13.61073
1994	12.79922
1995	15.08393
1996	18.90623
1997	20.98061
1998	19.28035
1999	20.87421
2000	19.16068
2001	18.53351
2002	19.17384
2003	19.6966
2004	19.61274
2005	20.46239
2006	18.15291
2007	19.19521
2008	25.91468
2009	21.81934