Year	Percent
1979-01-01	73.5714130362710
1980-01-01	74.0349555288420
1981-01-01	74.2043077233179
1982-01-01	74.2942941584514
1983-01-01	74.2166533884921
1984-01-01	74.8372666423854
1985-01-01	75.5352396409381
1986-01-01	77.1812266027672
1987-01-01	77.5707450397183
1988-01-01	78.3272570472186
1989-01-01	79.1783049177113
1990-01-01	80.1082228638817
1991-01-01	80.1263282008914
1992-01-01	79.9030334589264
1993-01-01	79.7193913842450
1994-01-01	79.6895941520042
1995-01-01	80.3771900218998
1996-01-01	80.2992994480920
1997-01-01	80.1666721033128
1998-01-01	80.0205923777856
1999-01-01	79.8490496415285
2000-01-01	80.2774921270689
2001-01-01	80.5529763715211
2002-01-01	80.7970529147874
2003-01-01	81.0976564332989
2004-01-01	80.7945579648196
2005-01-01	81.9292556841266
2006-01-01	82.2123652578202
2007-01-01	82.7280561959644
2008-01-01	83.1074492101365
2009-01-01	82.9113749968108
2010-01-01	82.8099917507692
2011-01-01	83.0727805523577
2012-01-01	82.8062202085884
2013-01-01	82.9207397348785
2014-01-01	82.8049555963892
2015-01-01	83.3651873141328
2016-01-01	83.4392258495153
2017-01-01	83.9248401108058