Year	Number
2004-01-01	16.1181
2005-01-01	20.9775
2006-01-01	33.1952
2007-01-01	40.6500
2008-01-01	47.7949
2009-01-01	52.1371
2010-01-01	53.3622
2011-01-01	54.8545
2012-01-01	54.0162
2013-01-01	53.9886
2014-01-01	53.3161
2015-01-01	52.5516
2016-01-01	53.9794
2017-01-01	53.1780