Year Number 2000 38000 2001 36000 2002 36000 2003 33000 2004 35000 2005 34000 2006 33000 2007 33000 2008 33000 2009 31000 2010 29000 2011 30000 2012 27000 2013 26000 2014 25000 2015 25000 2016 24000 2017 23000 2018 21000 2019 20000 2020 21000