Year	Percent
1991-01-01	13.1170357193758
1992-01-01	13.8025701929703
1993-01-01	15.0176576955888
1994-01-01	15.3017807088472
1995-01-01	15.3717026949143
1996-01-01	15.0879636620338
1997-01-01	14.4815380051980
1998-01-01	14.0740964490295
1999-01-01	13.8606208716073
2000-01-01	13.0703776863746
2001-01-01	13.2044633439875
2002-01-01	14.0965476409872
2003-01-01	14.5553625332228
2004-01-01	14.6314387795649
2005-01-01	14.1950388849502
2006-01-01	13.0841795389524
2007-01-01	12.3037491072454
2008-01-01	13.0463856841685
2009-01-01	16.8979265313711
2010-01-01	17.1943880131870
2011-01-01	16.7804861623629
2012-01-01	16.9152435860286
2013-01-01	16.9461082741496
2014-01-01	15.9885316269438
2015-01-01	14.7793565702943
2016-01-01	13.8644235209163
2017-01-01	12.7572274572279