Year	Percent
1990	85.521
1991	85.498
1992	85.369
1993	85.392
1994	85.459
1995	85.448
1996	85.421
1997	85.39
1998	85.359
1999	85.333
2000	85.313
2001	85.306
2002	85.303
2003	85.305
2004	85.31
2005	85.317
2006	85.315
2007	85.316
2008	85.668
2009	85.511
2010	83.725
2011	82.728
2012	84.104
2013	83.503
2014	82.739
2015	82.865
2016	83.989
2017	83.897
2018	83.81
2019	83.712
2020	83.592
2021	83.465
2022	83.318
2023	83.157
2024	82.993
2025	82.833
2026	82.688
2027	82.547
2028	82.406
2029	82.26
2030	82.106