Year	Number
2004-01-01	843
2005-01-01	1780
2006-01-01	2154
2007-01-01	4813
2008-01-01	7670
2009-01-01	9731
2010-01-01	11433
2011-01-01	13349
2012-01-01	14269
2013-01-01	15265
2014-01-01	16018
2015-01-01	16937
2016-01-01	17472
2017-01-01	17889