Year	Percent
1990	0.11077
1991	0.21462
1992	0.31058
1993	0.39883
1994	0.57697
1995	0.93042
1996	2.16837
1997	4.39941
1998	10.30707
1999	13.43612
2000	20.87379
2001	17.37862
2002	17.7646
2003	19.59339
2004	22.77049
2005	25.19404
2006	27.88107
2007	48.12806
2008	59.39
2009	63.12
2010	67.5
2011	68.87388
2012	70.8
2013	70.25031
2014	75.01775
2015	77.35209
2016	79.65312
2017	81.58118