Year	Percent
1973-01-01	97.51330000000000
1974-01-01	97.04630000000000
1975-01-01	94.42030000000000
1976-01-01	90.43700000000001
1977-01-01	90.41560000000000
1978-01-01	92.41000000000000
1979-01-01	93.79899999999999
1980-01-01	94.51350000000000
1981-01-01	95.31040000000000
1982-01-01	95.89160000000000
1983-01-01	96.14220000000000
1984-01-01	96.24630000000000
1985-01-01	96.48260000000000
1986-01-01	95.86670000000000
1987-01-01	97.57880000000000
1988-01-01	97.57880000000000
1989-01-01	99.98760000000000
1990-01-01	99.65980000000000
1991-01-01	99.69330000000000
1992-01-01	99.66890000000000
1993-01-01	99.69460000000000
1994-01-01	99.69460000000000
1995-01-01	99.69460000000000
1996-01-01	99.69460000000000
1997-01-01	99.69460000000000
1998-01-01	99.69460000000000
1999-01-01	99.69460000000000
2000-01-01	99.69460000000000
2001-01-01	99.98980000000000
2002-01-01	99.97110000000000
2003-01-01	99.96280000000000
2004-01-01	99.96820000000000
2005-01-01	99.58080000000000
2006-01-01	99.85590000000000
2007-01-01	99.93420000000000
2008-01-01	96.78510000000000
2009-01-01	92.12770000000000
2010-01-01	90.25370000000000
2011-01-01	90.94070000000000
2012-01-01	91.98930000000000
2013-01-01	94.07360000000000
2014-01-01	95.94020000000000
2015-01-01	96.38960000000000
2016-01-01	96.62230000000000