Year	Percent
1991	69.022
1992	68.641
1993	68.608
1994	68.36
1995	68.208
1996	68.024
1997	67.907
1998	67.831
1999	67.65
2000	67.616
2001	67.556
2002	67.432
2003	67.362
2004	67.24
2005	67.112
2006	67.009
2007	66.81
2008	66.53
2009	66.135
2010	66.014
2011	65.49
2012	64.952
2013	64.658
2014	64.309
2015	63.906
2016	63.599
2017	63.501
2018	63.435
2019	63.375
2020	63.324
2021	63.297
2022	63.288