Year	Percent
1990	73.299
1991	73.955
1992	74.405
1993	74.34
1994	75.076
1995	75.284
1996	75.369
1997	75.377
1998	74.459
1999	73.805
2000	73.696
2001	73.484
2002	74.151
2003	73.97
2004	74.317
2005	73.966
2006	73.549
2007	73.478
2008	72.753
2009	72.219
2010	72.158
2011	72.224
2012	72.393
2013	72.395
2014	73.241
2015	73.108
2016	73.152
2017	73.149
2018	73.157
2019	73.138
2020	73.071
2021	72.962
2022	72.806
2023	72.609
2024	72.384
2025	72.139
2026	71.879
2027	71.596
2028	71.29
2029	70.961
2030	70.61