Year	Percent
1986	16.59616
1987	14.79718
1988	15.00519
1989	34.0551
1990	45.27708
1991	36.03191
1992	38.83129
1993	37.48948
1994	43.46007
1995	41.90841
1996	51.83726
1997	51.24178
1998	52.15295
1999	52.82116
2000	57.4956
2001	56.894
2002	61.95773
2003	67.6547
2004	73.28546
2005	67.01535
2006	70.59681
2007	84.08751
2008	83.98079
2009	72.09743
2010	80.21501
2011	83.52368
2012	76.52531
2013	81.4681
2014	83.12975
2015	88.98817
2016	91.06234
2017	98.75402