Year	Percent
1991	69.305
1992	69.276
1993	68.856
1994	68.181
1995	67.62
1996	66.333
1997	65.584
1998	65.415
1999	64.415
2000	63.719
2001	63.487
2002	62.182
2003	62.243
2004	65.122
2005	69.294
2006	69.073
2007	69.361
2008	69.233
2009	70.299
2010	67.341
2011	64.068
2012	61.572
2013	67.139
2014	66.716
2015	66.156
2016	65.531
2017	64.084
2018	63.521
2019	62.958
2020	62.27
2021	61.507
2022	61.139