Year	Percent
1990	75.487
1991	75.475
1992	75.433
1993	75.284
1994	75.21
1995	75.041
1996	75.043
1997	75.171
1998	75.278
1999	75.309
2000	75.385
2001	75.348
2002	75.186
2003	75.394
2004	75.591
2005	75.619
2006	75.655
2007	75.102
2008	74.537
2009	74.561
2010	74.034
2011	74.502
2012	74.103
2013	73.924
2014	73.475
2015	73.439
2016	73.382
2017	73.241
2018	73.093
2019	72.949
2020	72.815
2021	72.661
2022	72.52
2023	72.386
2024	72.255
2025	72.122
2026	71.964
2027	71.809
2028	71.657
2029	71.509
2030	71.365