Year	Percent
1991	78.285
1992	78.101
1993	77.911
1994	77.721
1995	77.528
1996	77.359
1997	77.194
1998	77.016
1999	76.838
2000	76.678
2001	76.332
2002	77.947
2003	77.639
2004	77.328
2005	77.023
2006	76.783
2007	77.601
2008	78.167
2009	79.24
2010	78.774
2011	78.431
2012	77.984
2013	77.438
2014	77.402
2015	77.408
2016	77.348
2017	77.231
2018	77.112
2019	77
2020	76.897
2021	76.802
2022	76.714