Year	Percent
1991	68.68
1992	68.719
1993	68.265
1994	67.811
1995	67.364
1996	66.924
1997	66.485
1998	66.149
1999	64.672
2000	64.982
2001	65.844
2002	66.719
2003	67.606
2004	68.515
2005	69.44
2006	70.368
2007	70.157
2008	69.93
2009	69.751
2010	69.583
2011	70.426
2012	71.252
2013	72.55
2014	72.657
2015	72.762
2016	72.773
2017	72.866
2018	72.968
2019	73.064
2020	73.135
2021	73.18
2022	73.218