Year	Percent
1990	85.423
1991	85.398
1992	85.337
1993	85.236
1994	85.098
1995	84.907
1996	84.856
1997	84.754
1998	84.617
1999	84.472
2000	84.353
2001	84.367
2002	84.426
2003	84.524
2004	84.615
2005	84.678
2006	84.776
2007	84.778
2008	84.756
2009	84.729
2010	84.703
2011	84.7
2012	86.02
2013	87.257
2014	88.413
2015	88.293
2016	88.168
2017	88.282
2018	88.392
2019	88.498
2020	88.599
2021	88.701
2022	88.801
2023	88.901
2024	89.003
2025	89.11
2026	89.224
2027	89.342
2028	89.464
2029	89.593
2030	89.73