Year	Percent
1990	79.905
1991	79.945
1992	79.97
1993	79.991
1994	79.961
1995	79.946
1996	79.794
1997	79.633
1998	79.459
1999	79.269
2000	79.061
2001	78.85
2002	78.621
2003	78.376
2004	78.121
2005	77.861
2006	77.644
2007	77.424
2008	77.208
2009	77.009
2010	76.837
2011	76.815
2012	76.815
2013	76.805
2014	76.812
2015	76.8
2016	76.769
2017	76.879
2018	76.971
2019	77.033
2020	77.061
2021	77.069
2022	77.046
2023	76.999
2024	76.943
2025	76.886
2026	76.843
2027	76.801
2028	76.756
2029	76.704
2030	76.643