Year	Percent
1991	54.02741
1992	55.00637
1993	55.93127
1994	57.02033
1995	58.07058
1996	58.99832
1997	59.40409
1998	59.76277
1999	59.75023
2000	59.44551
2001	58.72602
2002	57.86601
2003	56.89885
2004	55.7739
2005	55.26207
2006	54.95835
2007	54.48959
2008	53.81117
2009	53.13248
2010	52.5563
2011	51.75334
2012	51.05216
2013	50.21516
2014	49.40207
2015	48.56314
2016	47.7652
2017	46.65333
2018	45.71877
2019	44.60826