Year Number 1996 8390.48 1997 8740.54 1998 8511.28 1999 8493.43 2000 9345.74 2001 9369.95 2002 9681.29 2003 9869.05 2004 10407.28 2005 10496.29 2006 11141.79 2007 11168.62 2008 11351.67 2009 11158.39 2010 10885.13 2011 11245 2012 11528.17 2013 11289.65 2014 11986.41 2015 12046.16 2016 12252.68 2017 12322.35 2018 12459.05 2019 13090.78 2020 13955.4