Year Number 2000 23000 2001 24000 2002 22000 2003 24000 2004 19000 2005 23000 2006 22000 2007 23000 2008 24000 2009 24000 2010 25000 2011 25000 2012 26000 2013 26000 2014 26000 2015 27000 2016 28000 2017 28000 2018 29000 2019 30000 2020 31000