Year	Percent
1999	16.81586
2000	16.3202
2001	16.73011
2002	17.20851
2003	17.70462
2004	17.78093
2005	17.21847
2006	17.3281
2007	16.79146
2008	17.70355
2009	19.51865
2010	20.12141
2011	20.22268
2013	20.80183
2014	21.22379