Year	Percent
1986-01-01	62.6878139851709
1987-01-01	62.4309416875209
1988-01-01	58.2058044126318
1989-01-01	53.7456835922316
1990-01-01	55.8293793479344
1991-01-01	52.5608287598504
1992-01-01	51.1066697479789
1993-01-01	50.7354853894065
1994-01-01	52.8763944299303
1995-01-01	55.3034902134545
1996-01-01	56.0652121270637
1997-01-01	55.2167811645004
1998-01-01	53.4077084625868
1999-01-01	51.5182474436640
2000-01-01	52.1445758763087
2001-01-01	52.6493438422631
2002-01-01	53.4472721424810
2003-01-01	53.1794995263896
2004-01-01	52.5023381254985
2005-01-01	53.1217181341522
2006-01-01	55.0623468281465
2007-01-01	55.6437503207265
2008-01-01	53.5658381559387
2009-01-01	48.6358680378038
2010-01-01	47.6809521464796
2011-01-01	47.6804444046682
2012-01-01	46.8843946624940
2013-01-01	47.4482596978191
2014-01-01	49.3870447332915
2015-01-01	51.0876755608257
2016-01-01	51.9638849036734
2017-01-01	53.3082230423977