Year	Months
2004-01-01	3.31093340918994
2005-01-01	3.53662816185651
2006-01-01	1.87611345966914
2007-01-01	1.63479381648149
2008-01-01	1.26932843654054
2009-01-01	1.91443845904439
2010-01-01	2.03859603936527
2011-01-01	2.58717349142966
2012-01-01	1.97407238690085
2013-01-01	1.81346352603877
2014-01-01	1.52831579698939
2015-01-01	1.93288275397974
2016-01-01	2.12653184551474
2017-01-01	2.02387421567363
2018-01-01	1.72443717401293
2019-01-01	1.71916011116924