Year	Percent
1991	49.94164
1992	49.98298
1993	50.31022
1994	49.76754
1995	49.38785
1996	48.97363
1997	48.31365
1998	48.34441
1999	48.12239
2000	47.96394
2001	47.74605
2002	47.29226
2003	46.60979
2004	46.50596
2005	46.70843
2006	46.29728
2007	46.14458
2008	45.67035
2009	44.96529
2010	44.22719
2011	43.43893
2012	42.64426
2013	41.81371
2014	41.02895
2015	38.78129
2016	36.41063
2017	33.97578
2018	33.27534
2019	32.52629