Year	Percent
2001	17.75793
2002	16.02941
2003	15.19025
2004	14.66496
2005	14.01936
2006	13.76361
2007	13.54176
2008	15.61642
2009	18.68962
2010	17.39084
2011	16.6681
2012	15.86289
2013	15.73752
2014	16.8938
2015	14.5691
2016	15.51978
2017	15.05257