Year	Percent
1991	72.646
1992	72.501
1993	72.241
1994	71.85
1995	71.504
1996	70.943
1997	70.306
1998	69.728
1999	69.102
2000	68.502
2001	68.265
2002	68.014
2003	67.741
2004	67.526
2005	67.349
2006	67.394
2007	66.571
2008	65.708
2009	64.804
2010	63.862
2011	62.888
2012	62.789
2013	62.629
2014	62.397
2015	62.084
2016	61.738
2017	61.491
2018	61.246
2019	61.011
2020	60.789
2021	60.58
2022	60.381