Year Number 1995 39240000 1996 39833000 1997 37315000 1998 33624000 1999 28803000 2000 31141000 2001 30679000 2002 31739000 2003 31412000 2004 33934000 2005 36173000 2006 38318000 2007 39379000 2008 39554000 2009 40624000 2010 39904000 2011 41304000 2012 43565000 2013 43611000 2014 45984000 2015 48345000 2016 52890000 2017 54962000 2018 57667000 2019 61397000 2020 31641000