Year	Percent
2000	21.6405
2001	22.2349
2002	22.6937
2003	22.1379
2004	20.5316
2005	19.5183
2006	18.6092
2007	17.4745
2008	16.393
2009	19.0119
2010	19.7886
2011	20.0827
2012	20.1532
2013	20.2841
2014	20.7594
2015	20.8129
2016	22.1753
2017	23.5293