Year	Percent
1991	52.433
1992	52.2
1993	52.001
1994	52.401
1995	51.957
1996	51.774
1997	50.829
1998	49.912
1999	49.166
2000	48.724
2001	49.265
2002	49.366
2003	49.392
2004	48.508
2005	47.732
2006	47.337
2007	47.159
2008	46.696
2009	46.198
2010	45.658
2011	44.982
2012	44.402
2013	43.963
2014	43.828
2015	43.523
2016	43.135
2017	43.79
2018	43.735
2019	43.679
2020	43.623
2021	43.569
2022	43.514