Year	Percent
1999	20.32225
2000	17.79399
2001	17.40294
2002	16.88527
2003	18.07602
2004	18.85264
2005	16.87732
2006	16.12182
2007	16.87032
2008	15.36874
2009	17.1948
2010	19.29048
2011	21.33641
2012	20.9676