Year	Percent
1991	57.147
1992	56.92
1993	56.743
1994	56.721
1995	56.625
1996	56.51
1997	56.503
1998	56.546
1999	56.669
2000	56.752
2001	56.851
2002	56.975
2003	57.153
2004	57.371
2005	57.556
2006	58.296
2007	59.18
2008	60.058
2009	60.71
2010	61.772
2011	63.081
2012	65.329
2013	65.42
2014	65.38
2015	65.301
2016	65.01
2017	64.578
2018	64.334
2019	64.016
2020	63.714
2021	63.454
2022	63.194