Year	Percent
1968-01-01	84.8877413792642
1969-01-01	84.7447616702560
1970-01-01	84.8802790775222
1971-01-01	85.4843035551626
1972-01-01	85.6286568049657
1973-01-01	85.7819165214105
1974-01-01	85.6626159842541
1975-01-01	85.3856615190468
1976-01-01	85.3457506572872
1977-01-01	84.8902278937826
1978-01-01	84.9196791012045
1979-01-01	84.9024711259076
1980-01-01	84.6655004899771
1981-01-01	84.7454047318404
1982-01-01	84.7496268090056
1983-01-01	84.7734292541939
1984-01-01	84.3510971546961
1985-01-01	83.7675311850095
1986-01-01	83.5305519291606
1987-01-01	83.2133669977766
1988-01-01	82.9402383145699
1989-01-01	82.9592037605843
1990-01-01	83.2566816481552
1991-01-01	83.7250641577774
1992-01-01	84.1851159587850
1993-01-01	84.4712773045596
1994-01-01	84.4772195163229
1995-01-01	84.5893370032906
1996-01-01	85.1170253792721
1997-01-01	85.4866587342094
1998-01-01	85.4192304427764
1999-01-01	85.4243689918693
2000-01-01	85.3766968919337
2001-01-01	85.1427242244699
2002-01-01	84.8469501981390
2003-01-01	84.7489181054228
2004-01-01	84.4160350965554
2005-01-01	84.5141158113122
2006-01-01	84.8641081207673
2007-01-01	85.3119546746869
2008-01-01	85.2899917045084
2009-01-01	84.9345637503418
2010-01-01	84.9355712863902
2011-01-01	84.8997154336172
2012-01-01	84.3833744545749
2013-01-01	84.6303122130013
2014-01-01	84.9290743720756
2015-01-01	85.0718457267210
2016-01-01	85.5521534443244
2017-01-01	85.6299522318391