Year	Percent
1990	82.778
1991	83.188
1992	83.388
1993	83.5
1994	83.791
1995	83.988
1996	83.927
1997	83.899
1998	84.101
1999	83.572
2000	83.446
2001	83.182
2002	82.63
2003	82.056
2004	81.78
2005	82.166
2006	82.697
2007	83.179
2008	82.607
2009	82.748
2010	82.59
2011	82.167
2012	82.538
2013	82.222
2014	82.792
2015	83.389
2016	83.392
2017	83.46
2018	83.544
2019	83.635
2020	83.729
2021	83.828
2022	83.931
2023	84.033
2024	84.127
2025	84.207
2026	84.274
2027	84.326
2028	84.364
2029	84.394
2030	84.419