Year Number of 1990 1344.83 1991 1366.97 1992 1376.55 1993 1381.26 1994 1370.57 1995 1388.41 1996 1397.57 1997 1406.57 1998 1422.9 1999 1441.7 2000 1446.2 2001 1466.78 2002 1489.88 2003 1512.11 2004 1531.24 2005 1542.27 2006 1551.29 2007 1566.1 2008 1585.28 2009 1592.08 2010 1587.54 2011 1583.59 2012 1589.96 2013 1598.98 2014 1615.29 2015 1669.79 2016 1720.48