Year	Number
2004-01-01	180
2005-01-01	175
2006-01-01	181
2007-01-01	178
2008-01-01	175
2009-01-01	171
2010-01-01	168
2011-01-01	163
2012-01-01	155
2013-01-01	155
2014-01-01	158
2015-01-01	157
2016-01-01	160