Year Number 2004-01-01 1288 2005-01-01 1670 2006-01-01 2271 2007-01-01 2841 2008-01-01 3465 2009-01-01 4203 2010-01-01 4821 2011-01-01 5258 2012-01-01 5999 2013-01-01 6488 2014-01-01 7290 2015-01-01 8431