Year	Percent
1990	85.465
1991	85.337
1992	85.12
1993	84.858
1994	84.501
1995	84.079
1996	83.83
1997	83.612
1998	83.43
1999	83.279
2000	83.121
2001	82.748
2002	82.298
2003	82.264
2004	81.937
2005	81.678
2006	81.379
2007	80.894
2008	80.496
2009	80.039
2010	79.622
2011	79.183
2012	78.918
2013	78.741
2014	78.655
2015	78.594
2016	78.589
2017	78.625
2018	78.668
2019	78.728
2020	78.807
2021	78.947
2022	79.105
2023	79.254
2024	79.36
2025	79.405
2026	79.44
2027	79.416
2028	79.348
2029	79.263
2030	79.179