Year	Number
2004-01-01	19.7889
2005-01-01	19.6020
2006-01-01	19.4059
2007-01-01	19.4556
2008-01-01	19.8257
2009-01-01	19.6829
2010-01-01	21.5533
2011-01-01	21.8775
2012-01-01	21.8517
2013-01-01	21.4858
2014-01-01	20.8537
2015-01-01	20.0646
2016-01-01	18.8576