Year	Percent
1980-01-01	96.8371
1981-01-01	97.1817
1982-01-01	97.1817
1983-01-01	97.1817
1984-01-01	97.1817
1985-01-01	97.1817
1986-01-01	97.1817
1987-01-01	97.1817
1988-01-01	97.1817
1989-01-01	97.1817
1990-01-01	97.1817
1991-01-01	97.1817
1992-01-01	97.1817
1993-01-01	97.1817
1994-01-01	97.1817
1995-01-01	97.1817
1996-01-01	97.1817
1997-01-01	97.1817
1998-01-01	97.1817
1999-01-01	97.1817
2000-01-01	97.1817
2001-01-01	99.7819
2002-01-01	99.5951
2003-01-01	99.1129
2004-01-01	98.6150
2005-01-01	98.6467
2006-01-01	98.7999
2007-01-01	98.9475
2008-01-01	99.2790
2009-01-01	99.4665
2010-01-01	99.4770
2011-01-01	99.6053
2012-01-01	99.7335
2013-01-01	99.7956
2014-01-01	99.8355
2015-01-01	99.8520
2016-01-01	99.8562