Year	Percent
1990	84.707
1991	84.567
1992	84.754
1993	84.642
1994	84.523
1995	84.345
1996	84.227
1997	84.017
1998	83.881
1999	84.246
2000	84.288
2001	84.112
2002	84.012
2003	83.802
2004	83.665
2005	83.422
2006	83.42
2007	83.066
2008	83.122
2009	83.067
2010	82.769
2011	82.493
2012	82.306
2013	82.12
2014	81.998
2015	81.891
2016	82.073
2017	82.11
2018	82.144
2019	82.169
2020	82.183
2021	82.185
2022	82.175
2023	82.154
2024	82.122
2025	82.079
2026	82.025
2027	81.96
2028	81.882
2029	81.787
2030	81.673