Year Number of 1990 7278.01 1991 7543.75 1992 7824.24 1993 8122.64 1994 8438.54 1995 8779.64 1996 9190.84 1997 9630.15 1998 10102.15 1999 10604.18 2000 11146.01 2001 11595.99 2002 12074.81 2003 12588.37 2004 13133.41 2005 13721.55 2006 14255.09 2007 14812.33 2008 15422.78 2009 16072.16 2010 16772.08 2011 17364.89 2012 17993.46 2013 18649.02 2014 19336.63 2015 20059.3 2016 20826.58