Year Number 1996 5949.63 1997 6304.13 1998 6222.3 1999 6264.67 2000 6614.6 2001 7073.06 2002 7505.6 2003 7854.83 2004 8060.2 2005 8921.33 2006 9110.6 2007 9799.94 2008 10300.65 2009 10837.18 2010 11058.41 2011 11683.33 2012 12050.36 2013 12201.98 2014 12408.16 2015 12840.55 2016 12668.55 2017 12756.54 2018 12713.75 2019 13162.53 2020 13700.08