Year Number of 1990 3944.75 1991 4049.2 1992 4164.88 1993 4292.8 1994 4431.34 1995 4592.44 1996 4677.04 1997 4765.4 1998 4861.77 1999 4956.03 2000 5063.05 2001 5146.29 2002 5225.08 2003 5301.38 2004 5376.34 2005 5454.66 2006 5464.11 2007 5477.52 2008 5494.56 2009 5514.75 2010 5542.14 2011 5569.99 2012 5586.8 2013 5615.21 2014 5644.99 2015 5676.09 2016 5709.55