Year	Percent
1990	86.368
1991	85.276
1992	84.439
1993	84.044
1994	84.034
1995	82.401
1996	83.161
1997	84.381
1998	84.425
1999	85.491
2000	85.131
2001	85.307
2002	85.856
2003	85.126
2004	84.752
2005	85.054
2006	85.259
2007	85.574
2008	85.848
2009	85.714
2010	84.446
2011	84.296
2012	84.103
2013	83.332
2014	83.646
2015	83.586
2016	82.753
2017	82.697
2018	82.642
2019	82.591
2020	82.547
2021	82.513
2022	82.486
2023	82.471
2024	82.468
2025	82.481
2026	82.511
2027	82.558
2028	82.614
2029	82.666
2030	82.704