Year Number of 1990 1130.7 1991 1151.35 1992 1187.79 1993 1211.08 1994 1239.56 1995 1268.01 1996 1292.02 1997 1335.29 1998 1385.58 1999 1434.56 2000 1466.56 2001 1480.6 2002 1489.35 2003 1496.95 2004 1524.42 2005 1562.25 2006 1584.04 2007 1586.01 2008 1580.81 2009 1583.48 2010 1590.59 2011 1596.52 2012 1609.2 2013 1635.97 2014 1665.52 2015 1688.88 2016 1709.73