Year	Percent
1999	17.29829
2000	15.52268
2001	15.00995
2002	16.34277
2004	16.75302
2006	14.4177
2007	14.79053
2008	16.10042
2009	21.05343
2010	24.27228
2011	23.04142
2012	24.60908
2013	24.5714
2014	24.9051
2015	26.46428
2016	24.53674