Year	Percent
1991-01-01	63.1409982488049
1992-01-01	63.2898925509015
1993-01-01	63.1482782922812
1994-01-01	62.9928847316312
1995-01-01	62.6394903814626
1996-01-01	62.3881427382324
1997-01-01	62.0853664352215
1998-01-01	61.7091811428458
1999-01-01	61.5669412356153
2000-01-01	61.4229744834951
2001-01-01	61.2649318432257
2002-01-01	61.0975106268504
2003-01-01	60.9298086352746
2004-01-01	60.8995660836564
2005-01-01	60.8782454203269
2006-01-01	60.7020917432112
2007-01-01	60.4888376038495
2008-01-01	60.0322754933235
2009-01-01	59.6093794590252
2010-01-01	59.3285092789320
2011-01-01	59.1437734567471
2012-01-01	58.9064990521433
2013-01-01	58.8069115595397
2014-01-01	58.6547891651933
2015-01-01	58.4111829006452
2016-01-01	58.2089160676631
2017-01-01	57.9725748611596