Year	Percent
2001	36.58
2002	35.85
2003	35.5
2004	35.9
2005	36.4
2006	36.6
2007	36.81
2008	36.83
2009	35.86
2010	35.92
2011	36.35
2012	36.23
2013	36.15
2014	36.13
2015	36.02
2016	35.88
2017	35.79