Year	Percent
1991	64.705
1992	64.902
1993	64.989
1994	64.974
1995	64.757
1996	64.825
1997	64.779
1998	64.657
1999	64.458
2000	64.24
2001	64.186
2002	64.036
2003	63.929
2004	63.783
2005	63.607
2006	63.516
2007	63.423
2008	63.196
2009	63.093
2010	62.947
2011	62.795
2012	62.601
2013	62.415
2014	62.272
2015	62.133
2016	61.876
2017	61.839
2018	61.8
2019	61.766
2020	61.738
2021	61.704
2022	61.672