Year	Percent
1998-01-01	4.07706601007941
1999-01-01	3.94412244425382
2000-01-01	3.21463857204655
2001-01-01	3.15375380392948
2002-01-01	4.11998505924397
2003-01-01	5.44023472925962
2004-01-01	5.80139512971155
2005-01-01	6.65294427984037
2006-01-01	6.53245396340086
2007-01-01	6.59517805673598
2008-01-01	6.47432065040227
2009-01-01	8.82958746899068
2010-01-01	9.75546298063451
2011-01-01	12.34796629338180
2012-01-01	15.55660188532710
2013-01-01	16.00795683626700
2014-01-01	13.48488354361210
2015-01-01	12.15588311706040
2016-01-01	10.97472181894610
2017-01-01	8.40869685594789