Year	Months
2004-01-01	2.89741952587741
2005-01-01	2.49420253123719
2006-01-01	2.01682016715416
2007-01-01	2.12126632759845
2008-01-01	2.98725091132318
2009-01-01	3.46965579669943
2010-01-01	2.62565656759769
2011-01-01	3.55085786700616
2012-01-01	3.06415566756631
2013-01-01	2.33611319846391
2014-01-01	2.70169121080574
2015-01-01	2.78879881938527
2016-01-01	3.00514942220369
2017-01-01	3.63858506192254
2018-01-01	3.80692453425723
2019-01-01	3.86114987209623