Year Number of 1990 292.23 1991 312.37 1992 334.23 1993 356.01 1994 378.61 1995 403.6 1996 421.97 1997 445.11 1998 467.93 1999 487.57 2000 509.23 2001 546.65 2002 586.78 2003 627.1 2004 668.88 2005 714.42 2006 737.19 2007 761.95 2008 786.05 2009 811.21 2010 837.86 2011 856.66 2012 880.15 2013 903.16 2014 929.29 2015 956.44 2016 984.61