Year	Percent
1991	54.81749
1992	55.48984
1993	56.19925
1994	56.79635
1995	57.11716
1996	56.76547
1997	55.16503
1998	54.22095
1999	53.27013
2000	51.95296
2001	51.43188
2002	50.81187
2003	51.90617
2004	51.34059
2005	50.68342
2006	49.91186
2007	49.10443
2008	48.48333
2009	47.95822
2010	47.30613
2011	46.44369
2012	45.55812
2013	44.60009
2014	44.22082
2015	43.91135
2016	43.74027
2017	43.21506
2018	42.77844
2019	42.61741