Year	Percent
1991	50.631
1992	50.305
1993	50.09
1994	49.751
1995	49.5
1996	49.383
1997	48.934
1998	48.394
1999	48.196
2000	48.19
2001	47.71
2002	47.76
2003	47.531
2004	46.966
2005	46.686
2006	46.275
2007	45.692
2008	45.527
2009	44.392
2010	44.223
2011	43.416
2012	42.94
2013	42.488
2014	42.111
2015	41.662
2016	41.135
2017	41.093
2018	41.01
2019	40.924
2020	40.838
2021	40.752
2022	40.667