Year	Percent
1991	63.832
1992	63.066
1993	65.076
1994	67.359
1995	67.649
1996	66.359
1997	64.647
1998	62.903
1999	62.083
2000	61.985
2001	61.308
2002	59.405
2003	58.958
2004	60.005
2005	61.142
2006	62.037
2007	63.59
2008	64.645
2009	62.206
2010	63.159
2011	64.193
2012	64.739
2013	65.297
2014	65.441
2015	65.942
2016	66.05
2017	66.293
2018	66.447
2019	66.331
2020	66.218
2021	66.112
2022	66.022