Year Number of 1990 3055.93 1991 3223.99 1992 3401.34 1993 3590.61 1994 3800.41 1995 4052.98 1996 4395.35 1997 4799.7 1998 5273.42 1999 5817.68 2000 6441.05 2001 6928.14 2002 7457.53 2003 8031.63 2004 8644.14 2005 9298.53 2006 9757.79 2007 10221.99 2008 10708.52 2009 11220.68 2010 11766.98 2011 12138.95 2012 12529.05 2013 12933.76 2014 13342.31 2015 13749.25 2016 14144.6