Year	Months
2004-01-01	4.81463789752324
2005-01-01	3.89401025004481
2006-01-01	4.00384262065339
2007-01-01	3.87202577802589
2008-01-01	4.25722779047472
2009-01-01	4.95353164465831
2010-01-01	3.43423737380103
2011-01-01	2.34486000414197
2012-01-01	2.58211478770840
2013-01-01	3.12707992579634
2014-01-01	3.47591624115710
2015-01-01	3.76755990710305
2016-01-01	2.82805657560757
2017-01-01	4.56222769020846
2018-01-01	2.94729531281706
2019-01-01	2.29442578845888