Year	Percent
1992	0.46388
1993	7.90554
1994	9.7011
1995	13.52571
1996	17.22475
1997	20.10612
1998	22.64949
1999	31.40165
2000	36.53972
2001	46.54565
2002	53.86545
2003	53.1516
2004	43.44182
2005	32.42838
2006	26.1795
2007	20.03131
2008	16.21438
2009	20.3189
2010	19.25047
2011	17.39346
2012	16.85415
2013	17.53168
2014	20.17061
2015	21.728
2016	23.7539