Year	Percent
1991	82.132
1992	82.014
1993	81.863
1994	80.842
1995	81.242
1996	82.232
1997	82.676
1998	82.579
1999	82.784
2000	83.077
2001	83.477
2002	83.94
2003	83.39
2004	81.364
2005	81.097
2006	81.582
2007	80.303
2008	80.729
2009	81.296
2010	81.777
2011	81.257
2012	81.246
2013	80.731
2014	80.66
2015	80.97
2016	81.376
2017	81.059
2018	81.189
2019	81.331
2020	81.711
2021	82.113
2022	82.533