Year	Percent
1990	74.554
1991	74.304
1992	74.121
1993	74.011
1994	73.985
1995	74.127
1996	73.988
1997	73.939
1998	73.963
1999	74.056
2000	74.174
2001	74.128
2002	74.154
2003	74.175
2004	74.244
2005	74.348
2006	74.381
2007	74.456
2008	74.603
2009	74.711
2010	74.864
2011	74.992
2012	75.164
2013	75.349
2014	75.528
2015	75.711
2016	75.941
2017	76.046
2018	76.151
2019	76.256
2020	76.36
2021	76.463
2022	76.565
2023	76.666
2024	76.766
2025	76.864
2026	76.962
2027	77.058
2028	77.154
2029	77.249
2030	77.344
