Year Number of 2000 15000 2001 15000 2002 17000 2003 15000 2004 17000 2005 18000 2006 19000 2007 19000 2008 19000 2009 19000 2010 21000 2011 19000 2012 17000 2013 16000 2014 14000 2015 11000 2016 9800 2017 8000 2018 8000 2019 6900 2020 6900