Year	Percent
1999-01-01	6.99595748255186
2000-01-01	6.41696329164505
2001-01-01	5.72701989745473
2002-01-01	5.82996602870869
2003-01-01	5.86975176556620
2004-01-01	6.07903296281181
2005-01-01	7.18830088848289
2006-01-01	7.49452044020281
2007-01-01	7.40647242614985
2008-01-01	7.81717362846026
2009-01-01	10.02932490815330
2010-01-01	11.17377515757780
2011-01-01	11.03269235462310
2012-01-01	11.00811764527190
2013-01-01	10.18523549978130
2014-01-01	7.72848580226153
2015-01-01	6.81780303639658
2016-01-01	5.11928515212164
2017-01-01	4.15716215385492