Year Number 1995 4398000 2004 11083000 2005 10417000 2006 10962000 2007 13479000 2008 17717000 2009 13319000 2010 13025000 2011 15776000 2012 19847000 2013 19934000 2014 23010000 2015 21834000 2016 20887000 2017 18607000 2018 17570000 2019 20292000