Year	Percent
1990	77.934
1991	78.091
1992	78.523
1993	78.558
1994	78.333
1995	77.965
1996	78.304
1997	78.13
1998	77.955
1999	77.801
2000	77.934
2001	77.863
2002	77.784
2003	78.149
2004	77.895
2005	77.888
2006	77.83
2007	77.757
2008	77.789
2009	77.808
2010	77.721
2011	77.869
2012	77.953
2013	80.518
2014	80.675
2015	80.625
2016	80.336
2017	80.448
2018	80.559
2019	80.671
2020	80.782
2021	80.893
2022	81.005
2023	81.116
2024	81.228
2025	81.339
2026	81.45
2027	81.562
2028	81.673
2029	81.785
2030	81.896