Year Number 2003 21119000 2004 22054000 2005 26927000 2006 26936000 2007 27138000 2008 26870000 2009 26571000 2010 26730000 2011 25811000 2012 26402000 2013 26516000 2014 28070000 2015 28209000 2016 28692000 2017 30736000 2018 30801000 2019 33093000 2020 15595000