Year	Percent
1998-01-01	2.75641454394517
1999-01-01	2.30741127376665
2000-01-01	2.25880699733469
2001-01-01	2.30095556707751
2002-01-01	2.77232817392145
2003-01-01	3.34748293482964
2004-01-01	3.50658325736915
2005-01-01	4.06128043565026
2006-01-01	4.21338450207710
2007-01-01	4.53328086765852
2008-01-01	4.17641474266301
2009-01-01	4.80850849137732
2010-01-01	5.68689137910367
2011-01-01	6.12749322786932
2012-01-01	7.30286427683310
2013-01-01	7.64818965924271
2014-01-01	6.67385706988111