Year	Percent
1990	81.581
1991	81.667
1992	81.663
1993	81.77
1994	81.545
1995	81.256
1996	81.202
1997	81.131
1998	81.029
1999	80.922
2000	80.798
2001	80.832
2002	80.919
2003	80.858
2004	80.739
2005	80.557
2006	80.534
2007	80.441
2008	80.393
2009	80.441
2010	80.452
2011	80.555
2012	80.574
2013	80.515
2014	80.419
2015	80.283
2016	80.179
2017	80.092
2018	79.994
2019	79.891
2020	79.788
2021	79.687
2022	79.586
2023	79.493
2024	79.419
2025	79.368
2026	79.338
2027	79.328
2028	79.333
2029	79.35
2030	79.376