Year	Percent
1990	82.101
1991	82.071
1992	82.023
1993	81.972
1994	81.917
1995	81.864
1996	81.843
1997	81.808
1998	81.767
1999	81.733
2000	81.709
2001	81.704
2002	81.722
2003	81.752
2004	81.788
2005	81.819
2006	81.841
2007	81.858
2008	81.86
2009	81.873
2010	81.906
2011	81.98
2012	81.359
2013	80.552
2014	79.532
2015	79.535
2016	79.529
2017	79.46
2018	79.386
2019	79.315
2020	79.25
2021	79.191
2022	79.136
2023	79.083
2024	79.028
2025	78.97
2026	78.911
2027	78.852
2028	78.791
2029	78.729
2030	78.667