Year	Percent
1979-01-01	91.8407381727102
1980-01-01	91.6064021876237
1981-01-01	91.3692308634607
1982-01-01	90.0360961824006
1983-01-01	87.5875329701751
1984-01-01	88.1526929348963
1985-01-01	88.1813093520941
1986-01-01	88.4776598193582
1987-01-01	88.0020536467559
1988-01-01	88.6183241424238
1989-01-01	89.0567059668420
1990-01-01	88.7316857489744
1991-01-01	86.0650856439534
1992-01-01	84.3955843578445
1993-01-01	83.8509008672544
1994-01-01	84.3957952074774
1995-01-01	85.3433842901049
1996-01-01	85.4031835104828
1997-01-01	84.9972740412088
1998-01-01	85.0559912950201
1999-01-01	85.3890468210676
2000-01-01	85.5801031665307
2001-01-01	85.2638913799014
2002-01-01	85.6121523530310
2003-01-01	85.7271454279805
2004-01-01	86.3160869775278
2005-01-01	87.0119701222344
2006-01-01	87.2209018258233
2007-01-01	88.1036501841530
2008-01-01	88.2904207791768
2009-01-01	86.2786016376482
2010-01-01	87.1702187996174
2011-01-01	87.3641435145928
2012-01-01	86.7159716778334
2013-01-01	86.1409151499724
2014-01-01	85.7379449383319
2015-01-01	86.1778193593732
2016-01-01	86.4647459773914
2017-01-01	86.6422839807370