Year	Percent
1990	49.55123
1991	36.62885
1992	47.59207
1993	41.17504
1994	40.06839
1995	42.35898
1996	56.55767
1997	46.19024
1998	58.026
1999	56.99653
2000	47.58291
2001	37.02244
2002	43.33944
2003	45.25155
2004	51.2598
2005	56.77845
2006	79.02937
2007	84.14541
2008	92.55713
2009	78.68081
2010	81.67853
2011	81.64136
2012	95.27174
2013	91.77663
2014	87.67753
2015	75.77197
2016	69.99817
2017	66.78859