Year	Percent
1990	77.705
1991	77.686
1992	77.669
1993	77.65
1994	77.505
1995	77.318
1996	77.162
1997	76.946
1998	76.687
1999	76.466
2000	76.25
2001	76.056
2002	75.885
2003	75.741
2004	75.602
2005	75.461
2006	75.333
2007	75.208
2008	75.091
2009	74.988
2010	74.895
2011	74.791
2012	74.696
2013	74.611
2014	74.54
2015	74.482
2016	74.439
2017	74.412
2018	74.38
2019	74.309
2020	74.182
2021	74.003
2022	73.773
2023	73.513
2024	73.254
2025	73.013
2026	72.777
2027	72.562
2028	72.352
2029	72.124
2030	71.865