Year	Percent
1990	84.895
1991	84.814
1992	84.725
1993	85.58
1994	85.385
1995	85.504
1996	85.65
1997	85.642
1998	85.567
1999	85.761
2000	85.954
2001	85.754
2002	85.637
2003	85.281
2004	84.274
2005	83.725
2006	83.858
2007	83.841
2008	83.796
2009	83.68
2010	83.181
2011	83.262
2012	82.955
2013	82.753
2014	82.477
2015	82.396
2016	82.737
2017	82.55
2018	82.362
2019	82.175
2020	81.988
2021	81.801
2022	81.614
2023	81.427
2024	81.24
2025	81.052
2026	80.865
2027	80.678
2028	80.491
2029	80.304
2030	80.117