Year	Percent
1986-01-01	84.4909333369513
1987-01-01	83.3656157687826
1988-01-01	79.7732363649046
1989-01-01	77.2978647759060
1990-01-01	76.1458840486266
1991-01-01	73.5176843172198
1992-01-01	72.9465365566694
1993-01-01	73.8403870025631
1994-01-01	75.7148842275412
1995-01-01	78.1966283224118
1996-01-01	78.5388371177770
1997-01-01	78.1300931290198
1998-01-01	76.7404241916599
1999-01-01	76.8285541343799
2000-01-01	77.8193725302325
2001-01-01	78.6030465079397
2002-01-01	79.4741184739472
2003-01-01	79.1937775030235
2004-01-01	80.6252290480155
2005-01-01	81.3287783380566
2006-01-01	81.9026326371164
2007-01-01	81.9790890062445
2008-01-01	80.9174096230596
2009-01-01	78.6314612083938
2010-01-01	78.2103410157291
2011-01-01	78.2569383014830
2012-01-01	77.4282635750392
2013-01-01	78.2507473326464
2014-01-01	79.6920530580100
2015-01-01	79.6113251094396
2016-01-01	80.6864929452520
2017-01-01	81.8825838771086