Year	Percent
1991	61.73
1992	61.861
1993	61.788
1994	61.882
1995	61.837
1996	61.58
1997	61.511
1998	61.247
1999	60.655
2000	61.72
2001	62.967
2002	64.303
2003	65.542
2004	66.478
2005	67.707
2006	67.73
2007	67.695
2008	67.65
2009	67.608
2010	67.548
2011	67.514
2012	67.553
2013	67.742
2014	66.873
2015	65.993
2016	65.075
2017	65.008
2018	64.952
2019	64.898
2020	64.84
2021	64.78
2022	64.718