Year	Months
2004-01-01	3.64416188573429
2005-01-01	3.97511712598690
2006-01-01	4.77815396089127
2007-01-01	5.92141595091768
2008-01-01	4.94476294845575
2009-01-01	5.30038634555285
2010-01-01	4.31023658239190
2011-01-01	3.94123455267121
2012-01-01	5.47824128151257
2013-01-01	5.39663254222086
2014-01-01	6.18069350951049
2015-01-01	5.84293046098775
2016-01-01	4.42272062937061
2017-01-01	4.15725201152740
2018-01-01	3.52167960651575
2019-01-01	3.65051772922332