Year Number of 1990 1555.75 1991 1616.49 1992 1613.72 1993 1664.68 1994 1666.76 1995 1711.26 1996 1679.45 1997 1667.57 1998 1654.98 1999 1729.13 2000 1566.19 2001 1505.59 2002 1491.39 2003 1551.52 2004 1479.7 2005 1494.66 2006 1458.44 2007 1381.99 2008 1336.58 2009 1430.99 2010 1456.3 2011 1479.58 2012 1490.18 2013 1545.5 2014 1573.46 2015 1599.29 2016 1626.68