Year	Percent
1991	99.14
1992	99.137
1993	99.181
1994	99.055
1995	99.106
1996	98.982
1997	98.981
1998	99.007
1999	99.004
2000	98.939
2001	98.821
2002	98.823
2003	98.717
2004	98.265
2005	98.61
2006	98.698
2007	98.675
2008	98.633
2009	98.649
2010	98.481
2011	98.623
2012	98.506
2013	98.509
2014	98.475
2015	98.595
2016	98.738
2017	98.74
2018	98.736
2019	98.731
2020	98.727
2021	98.723
2022	98.719