Year	Number
2004-01-01	17.5641
2005-01-01	19.2276
2006-01-01	21.3690
2007-01-01	21.4378
2008-01-01	22.7038
2009-01-01	24.2128
2010-01-01	24.9279
2011-01-01	26.1855
2012-01-01	26.7140
2013-01-01	27.3092
2014-01-01	29.8033
2015-01-01	30.4319
2016-01-01	31.7647