Year	Percent
1986-01-01	73.4381753036352
1987-01-01	73.4472120850596
1988-01-01	74.7631728372711
1989-01-01	75.8499361255561
1990-01-01	75.5547424606041
1991-01-01	75.7283930627176
1992-01-01	75.5864281166687
1993-01-01	77.2254367039172
1994-01-01	77.5273677616700
1995-01-01	76.6521643213638
1996-01-01	75.4421789729598
1997-01-01	74.6911420330676
1998-01-01	74.7613487964168
1999-01-01	74.6419258567661
2000-01-01	73.9075552256049
2001-01-01	73.4278346547461
2002-01-01	73.0093668821664
2003-01-01	72.9458567448781
2004-01-01	72.5031012482032
2005-01-01	72.4242011246383
2006-01-01	71.6719367553886
2007-01-01	71.3740986724159
2008-01-01	71.7852405050793
2009-01-01	70.9941956094029
2010-01-01	72.0871073569606
2011-01-01	72.7106116957615
2012-01-01	71.9259771429928
2013-01-01	71.8042083713377
2014-01-01	71.5785384393997
2015-01-01	71.4828133975493
2016-01-01	71.2670248189472
2017-01-01	71.2270463869920