Year	Percent
1998-01-01	7.72943780108148
1999-01-01	5.68193504168636
2000-01-01	4.40036625278407
2001-01-01	4.01031409346970
2002-01-01	4.70337943576025
2003-01-01	5.01957652386151
2004-01-01	4.87479526493931
2005-01-01	4.58289100009801
2006-01-01	4.56116974714842
2007-01-01	5.01965097962213
2008-01-01	7.60214252017482
2009-01-01	15.08203558310500
2010-01-01	17.06698865726970
2011-01-01	17.69297734617230
2012-01-01	17.68107332495800
2013-01-01	14.85070814461530
2014-01-01	12.67648542756650
2015-01-01	10.73184256236620
2016-01-01	9.02272120915783
2017-01-01	7.06478389686556