Year	Percent
1991	77.924
1992	78.145
1993	78.3
1994	78.358
1995	78.278
1996	78.113
1997	77.861
1998	77.555
1999	77.261
2000	77.56
2001	77.889
2002	78.238
2003	78.588
2004	78.914
2005	79.229
2006	79.013
2007	78.763
2008	78.484
2009	78.198
2010	77.928
2011	77.708
2012	77.503
2013	77.427
2014	76.287
2015	75.093
2016	73.96
2017	73.873
2018	73.785
2019	73.686
2020	73.579
2021	73.465
2022	73.348