Year	Percent
1990	78.91
1991	78.788
1992	78.7
1993	78.578
1994	78.462
1995	78.301
1996	78.125
1997	78.036
1998	78.484
1999	78.422
2000	78.261
2001	78.169
2002	77.944
2003	77.744
2004	77.554
2005	77.467
2006	77.189
2007	76.83
2008	76.283
2009	76.193
2010	76.139
2011	76.705
2012	77.294
2013	77.588
2014	77.238
2015	77.368
2016	77.138
2017	77.346
2018	77.534
2019	77.697
2020	77.831
2021	77.92
2022	77.978
2023	78.004
2024	77.996
2025	77.952
2026	77.86
2027	77.736
2028	77.586
2029	77.421
2030	77.248