Year	Percent
1990	86.05
1991	86.022
1992	85.928
1993	85.732
1994	85.627
1995	85.463
1996	85.413
1997	85.377
1998	85.372
1999	85.331
2000	85.287
2001	85.517
2002	85.693
2003	85.808
2004	85.888
2005	85.933
2006	85.323
2007	84.687
2008	84.021
2009	83.319
2010	82.581
2011	81.881
2012	81.155
2013	80.923
2014	80.659
2015	80.38
2016	80.145
2017	80.053
2018	79.966
2019	79.894
2020	79.845
2021	79.82
2022	79.811
2023	79.813
2024	79.818
2025	79.821
2026	79.832
2027	79.842
2028	79.847
2029	79.843
2030	79.828