Year Number of 1990 431.96 1991 458.72 1992 478.24 1993 501.88 1994 525.81 1995 551.57 1996 578.12 1997 608.87 1998 641.75 1999 678.87 2000 720.81 2001 756.73 2002 796.76 2003 832.46 2004 868.24 2005 908.97 2006 954.51 2007 1013.87 2008 1074.47 2009 1133.42 2010 1200.31 2011 1249.28 2012 1343.78 2013 1440.99 2014 1511.66 2015 1529.51 2016 1543.1