Year Number 2004-01-01 480564 2005-01-01 339684 2006-01-01 123596 2007-01-01 224904 2008-01-01 237298 2009-01-01 270206 2010-01-01 355590 2011-01-01 425353 2012-01-01 501698 2013-01-01 548880