Year Number of 1990 1384.76 1991 1392.08 1992 1397.19 1993 1400.45 1994 1387.94 1995 1395.79 1996 1398.47 1997 1396.13 1998 1410.02 1999 1450.42 2000 1476.25 2001 1501.98 2002 1517.32 2003 1528.34 2004 1565.15 2005 1566.31 2006 1568.38 2007 1587.35 2008 1585.4 2009 1569.62 2010 1551.78 2011 1550.08 2012 1568.71 2013 1568.68 2014 1559.3 2015 1570.48 2016 1583.76