Year	Percent
1990	87.453
1991	87.65
1992	87.707
1993	87.708
1994	87.519
1995	87.248
1996	86.921
1997	86.477
1998	85.887
1999	85.161
2000	84.259
2001	83.306
2002	82.204
2003	81.014
2004	79.723
2005	78.503
2006	77.654
2007	76.82
2008	76.174
2009	75.707
2010	75.244
2011	74.79
2012	74.396
2013	74.04
2014	73.715
2015	73.456
2016	73.161
2017	73.347
2018	73.516
2019	73.664
2020	73.789
2021	73.912
2022	74.015
2023	74.096
2024	74.16
2025	74.211
2026	74.263
2027	74.305
2028	74.335
2029	74.345
2030	74.333