Year Number of 1990 1301.36 1991 1327.15 1992 1339.71 1993 1345.87 1994 1341.82 1995 1295.97 1996 1296.5 1997 1260.45 1998 1262.37 1999 1283.35 2000 1284.82 2001 1309.63 2002 1329.14 2003 1374.09 2004 1376.1 2005 1327.09 2006 1373.92 2007 1378.56 2008 1393.54 2009 1409.19 2010 1428.19 2011 1462.87 2012 1481.26 2013 1467.67 2014 1466.68 2015 1460.45 2016 1492.04