Year	Percent
1991	71.245
1992	70.766
1993	70.485
1994	70.431
1995	70.049
1996	69.806
1997	69.299
1998	69.081
1999	69.037
2000	68.871
2001	68.382
2002	68.107
2003	68.003
2004	67.46
2005	67.26
2006	66.866
2007	66.467
2008	65.924
2009	65.898
2010	65.572
2011	64.833
2012	64.461
2013	64.115
2014	63.829
2015	63.395
2016	63.222
2017	63.163
2018	63.115
2019	63.061
2020	63.003
2021	62.941
2022	62.877