Year	Percent
1990	83.793
1991	83.749
1992	83.444
1993	83.23
1994	83.106
1995	83.034
1996	82.759
1997	82.556
1998	82.421
1999	82.325
2000	82.221
2001	81.468
2002	81.029
2003	80.771
2004	80.67
2005	80.647
2006	80.111
2007	79.643
2008	79.332
2009	79.184
2010	79.123
2011	79.052
2012	78.887
2013	78.668
2014	78.454
2015	78.147
2016	77.852
2017	77.828
2018	77.815
2019	77.818
2020	77.841
2021	77.882
2022	77.949
2023	78.016
2024	78.045
2025	78.01
2026	77.916
2027	77.76
2028	77.565
2029	77.363
2030	77.175