Year	Percent
1991	64.336
1992	63.97
1993	63.909
1994	62.877
1995	61.59
1996	60.285
1997	59.613
1998	60.482
1999	61.16
2000	61.241
2001	60.796
2002	60.695
2003	62.438
2004	60.885
2005	59.341
2006	58.817
2007	58.212
2008	58.657
2009	57.932
2010	56.951
2011	53.728
2012	50.821
2013	49.546
2014	48.977
2015	46.428
2016	46.762
2017	46.649
2018	46.572
2019	46.494
2020	46.416
2021	46.337
2022	46.258