Year	Percent
1991-01-01	14.2566495962079
1992-01-01	13.9400518951567
1993-01-01	14.1774231843338
1994-01-01	14.3920635752373
1995-01-01	13.8612363737480
1996-01-01	14.3148507672810
1997-01-01	14.4279028680258
1998-01-01	14.2646903545526
1999-01-01	14.3135440157915
2000-01-01	14.8235312179919
2001-01-01	15.4769410762492
2002-01-01	15.6355932764637
2003-01-01	15.2574017590081
2004-01-01	15.7068069043784
2005-01-01	15.6569978842351
2006-01-01	15.7242267325432
2007-01-01	15.7498506376959
2008-01-01	16.0175938303122
2009-01-01	15.2033663089245
2010-01-01	15.8322722478286
2011-01-01	16.2917854953700
2012-01-01	16.0244724615837
2013-01-01	16.0499482474082
2014-01-01	16.0205266638922
2015-01-01	16.3630884106672
2016-01-01	16.3011662733971
2017-01-01	16.3757000910814