Year	Months
2004-01-01	2.56690434167550
2005-01-01	2.93735535819804
2006-01-01	3.15825057938141
2007-01-01	3.69700163874366
2008-01-01	5.00039737713004
2009-01-01	4.63412859555821
2010-01-01	4.25463863760213
2011-01-01	4.74583433628446
2012-01-01	4.98482843311102
2013-01-01	5.14357034945547
2014-01-01	5.89697153539472
2015-01-01	6.17606557166639
2016-01-01	5.72713946577208
2017-01-01	5.58972001199705
2018-01-01	5.45727184618237
2019-01-01	5.15314535414332