Year	Percent
1979-01-01	94.8002681674980
1980-01-01	94.6146651833321
1981-01-01	94.3079042695436
1982-01-01	94.1352661169122
1983-01-01	94.1104197073795
1984-01-01	93.9538229417698
1985-01-01	93.4451134466891
1986-01-01	93.6110487886468
1987-01-01	93.2873425590962
1988-01-01	93.0475518026935
1989-01-01	92.9375218575987
1990-01-01	93.2752219117192
1991-01-01	93.0773657744889
1992-01-01	92.4378513268856
1993-01-01	92.2415747189777
1994-01-01	91.5985813790981
1995-01-01	91.7214431046140
1996-01-01	91.5756342060344
1997-01-01	91.0639154675297
1998-01-01	90.8072437087059
1999-01-01	90.4291407101028
2000-01-01	90.2237693051089
2001-01-01	90.1372179464430
2002-01-01	90.1790504535608
2003-01-01	89.8445342548008
2004-01-01	89.8732854827032
2005-01-01	90.3107250306346
2006-01-01	90.3292500833001
2007-01-01	90.7831993503003
2008-01-01	90.9331478295590
2009-01-01	90.3543476242100
2010-01-01	90.5626692895258
2011-01-01	90.5997366113917
2012-01-01	90.1371323157330
2013-01-01	90.1381742732743
2014-01-01	89.8625210763855
2015-01-01	90.2969731545769
2016-01-01	90.1554714778415
2017-01-01	90.3152753406890