Year	Number
2004-01-01	15.3222
2005-01-01	16.1912
2006-01-01	16.8553
2007-01-01	17.7026
2008-01-01	18.5296
2009-01-01	19.0201
2010-01-01	19.6566
2011-01-01	20.2194
2012-01-01	20.9347
2013-01-01	20.9060
2014-01-01	19.3680
2015-01-01	19.7788
2016-01-01	19.8979