Year	Percent
1990	89.674
1991	89.683
1992	89.65
1993	89.615
1994	89.565
1995	89.503
1996	89.441
1997	89.386
1998	89.345
1999	89.302
2000	89.237
2001	89.17
2002	89.097
2003	89.024
2004	88.956
2005	88.9
2006	88.856
2007	88.82
2008	88.791
2009	88.769
2010	89.177
2011	89.579
2012	89.969
2013	90.348
2014	90.391
2015	89.344
2016	89.616
2017	89.722
2018	89.829
2019	89.938
2020	90.049
2021	90.162
2022	90.277
2023	90.39
2024	90.5
2025	90.604
2026	90.705
2027	90.803
2028	90.897
2029	90.989
2030	91.079