Year	Percent
1990	86.568
1991	86.456
1992	86.324
1993	86.162
1994	85.961
1995	85.719
1996	85.447
1997	85.149
1998	84.831
1999	84.5
2000	84.163
2001	83.741
2002	83.295
2003	82.842
2004	82.406
2005	82.006
2006	81.644
2007	81.327
2008	81.031
2009	80.713
2010	80.342
2011	80.333
2012	80.296
2013	80.244
2014	80.189
2015	80.133
2016	80.066
2017	79.735
2018	79.4
2019	79.085
2020	78.806
2021	78.563
2022	78.354
2023	78.178
2024	78.031
2025	77.909
2026	77.817
2027	77.759
2028	77.713
2029	77.647
2030	77.534