Year	Percent
1990	73.833
1991	73.784
1992	73.712
1993	73.686
1994	73.56
1995	73.515
1996	73.511
1997	73.496
1998	73.459
1999	73.456
2000	73.451
2001	73.508
2002	73.547
2003	73.59
2004	73.625
2005	73.654
2006	73.165
2007	72.661
2008	72.144
2009	71.61
2010	71.06
2011	70.543
2012	70.021
2013	70.056
2014	70.084
2015	70.1
2016	70.128
2017	70.132
2018	70.14
2019	70.16
2020	70.193
2021	70.237
2022	70.292
2023	70.353
2024	70.413
2025	70.467
2026	70.517
2027	70.563
2028	70.603
2029	70.635
2030	70.657