Year	Percent
1986-01-01	75.3427528411866
1987-01-01	75.1832881900466
1988-01-01	73.7366646891076
1989-01-01	72.5045584127588
1990-01-01	72.9803398333506
1991-01-01	73.1058304479822
1992-01-01	72.7839404695393
1993-01-01	72.8382936324496
1994-01-01	73.7295134597918
1995-01-01	74.5222546594340
1996-01-01	75.4187947636901
1997-01-01	75.3454532041093
1998-01-01	74.9296817982832
1999-01-01	74.8904212115092
2000-01-01	74.9950485061998
2001-01-01	75.5580678137487
2002-01-01	76.1817566777815
2003-01-01	75.8216593735991
2004-01-01	76.2847198699225
2005-01-01	77.2102763267917
2006-01-01	77.8126814427088
2007-01-01	78.0033342169957
2008-01-01	77.7971124866096
2009-01-01	77.4383990758610
2010-01-01	77.0969434567029
2011-01-01	77.2929393396274
2012-01-01	77.1079515743672
2013-01-01	77.4888221917658
2014-01-01	78.6390795741273
2015-01-01	78.6849801891045
2016-01-01	79.8456836806924
2017-01-01	80.8660337181231