Year	Percent
1990	86.721
1991	86.125
1992	85.056
1993	84.02
1994	83.591
1995	83.127
1996	82.943
1997	82.868
1998	82.541
1999	82.613
2000	82.681
2001	81.97
2002	81.775
2003	81.926
2004	81.545
2005	81.805
2006	82.074
2007	81.995
2008	82.215
2009	81.719
2010	81.325
2011	81.273
2012	81.756
2013	81.867
2014	81.973
2015	82.031
2016	82.285
2017	82.363
2018	82.42
2019	82.448
2020	82.442
2021	82.38
2022	82.277
2023	82.155
2024	82.048
2025	81.977
2026	81.914
2027	81.883
2028	81.882
2029	81.904
2030	81.945