Year	Percent
1990	73.96
1991	74.449
1992	75.103
1993	75.884
1994	76.339
1995	76.727
1996	77.017
1997	77.159
1998	77.114
1999	77.204
2000	77.134
2001	77.107
2002	77.009
2003	76.97
2004	76.844
2005	76.664
2006	76.585
2007	76.412
2008	76.35
2009	76.499
2010	76.492
2011	76.374
2012	76.351
2013	76.396
2014	76.422
2015	76.395
2016	76.371
2017	76.338
2018	76.291
2019	76.244
2020	76.202
2021	76.125
2022	76.047
2023	75.97
2024	75.896
2025	75.826
2026	75.729
2027	75.634
2028	75.547
2029	75.472
2030	75.413