Year	Percent
1991	67.666
1992	67.693
1993	67.108
1994	67.965
1995	67.561
1996	65.984
1997	65.518
1998	65.243
1999	65.895
2000	65.612
2001	65.229
2002	64.742
2003	64.523
2004	61.106
2005	62.532
2006	63.036
2007	64.181
2008	64.537
2009	63.381
2010	63.533
2011	63.596
2012	63.359
2013	63.065
2014	62.248
2015	61.979
2016	61.967
2017	62.111
2018	61.969
2019	61.704
2020	61.442
2021	61.11
2022	60.749