Year	Percent
1991	80.415
1992	80.667
1993	81.339
1994	82.336
1995	81.875
1996	82.481
1997	81.9
1998	81.407
1999	81.225
2000	81.25
2001	80.825
2002	80.702
2003	80.974
2004	80.927
2005	80.67
2006	81.329
2007	81.173
2008	81.532
2009	82.769
2010	83.409
2011	82.639
2012	82.855
2013	83.214
2014	83.779
2015	84.453
2016	83.574
2017	82.996
2018	82.64
2019	82.418
2020	82.263
2021	81.568
2022	80.962