Year Number 1996 1469.22 1997 1403.3 1998 1495.5 1999 1547.68 2000 1828.44 2001 1878.8 2002 2124.29 2003 2379.73 2004 2523.44 2005 2996.18 2006 2968.51 2007 3473.85 2008 3718.57 2009 4131.55 2010 3970.63 2011 4529.57 2012 4432.34 2013 4239.71 2014 4021.73 2015 4079.08 2016 4029.84 2017 4359.05 2018 4619.34 2019 4594.8 2020 4800.05