Year	Percent
1991	87.325
1992	86.163
1993	86.716
1994	86.103
1995	85.731
1996	85.893
1997	85.507
1998	84.723
1999	83.94
2000	86.893
2001	86.55
2002	85.897
2003	85.32
2004	85.468
2005	84.512
2006	83.105
2007	82.35
2008	81.435
2009	81.128
2010	79.603
2011	78.524
2012	79.987
2013	79.872
2014	79.537
2015	78.927
2016	77.687
2017	77.691
2018	77.608
2019	77.525
2020	77.444
2021	77.365
2022	77.289