Year Number 1995 15298000 1996 16695000 1997 16803000 1998 15806000 1999 16358000 2000 17819000 2001 16216000 2002 16523000 2003 13296000 2004 16831000 2005 17404000 2006 17535000 2007 17295000 2008 15987000 2009 15446000 2010 16637000 2011 16994000 2012 18491000 2013 17473000 2014 16903000 2015 16214000 2016 17116000 2017 17889000 2018 18954000 2019 20081000 2020 3174000