Year	Percent
1991	77.961
1992	77.968
1993	78.003
1994	77.963
1995	77.967
1996	77.945
1997	77.909
1998	77.874
1999	77.802
2000	77.695
2001	77.61
2002	77.483
2003	77.352
2004	77.2
2005	76.878
2006	76.767
2007	76.66
2008	76.554
2009	76.466
2010	76.335
2011	76.32
2012	76.329
2013	76.327
2014	76.346
2015	76.344
2016	76.306
2017	76.408
2018	76.492
2019	76.548
2020	76.57
2021	76.574
2022	76.547