Year	Percent
1990	74.751
1991	74.749
1992	74.769
1993	74.758
1994	74.746
1995	74.724
1996	74.699
1997	74.681
1998	74.663
1999	74.634
2000	74.594
2001	74.56
2002	74.527
2003	74.51
2004	74.533
2005	74.613
2006	74.733
2007	74.896
2008	75.106
2009	75.367
2010	75.678
2011	76.014
2012	76.392
2013	76.783
2014	77.146
2015	77.453
2016	77.685
2017	77.875
2018	78.007
2019	78.054
2020	78.003
2021	77.84
2022	77.592
2023	77.29
2024	76.977
2025	76.679
2026	76.384
2027	76.108
2028	75.859
2029	75.641
2030	75.455