Year	Percent
2000	38.94
2001	38.56
2002	36.21
2003	41.53
2004	38.48
2005	37.52
2006	34.08
2007	33.56
2008	32.64
2009	32.92
2010	33.45
2011	32.84
2012	32.07
2013	30.8
2014	30.02
2015	28.15
2016	26.04
2017	25.21