Year Number of 1990 186.14 1991 192.34 1992 198.84 1993 206.29 1994 214.17 1995 222.48 1996 235.83 1997 249.9 1998 265.08 1999 281.13 2000 298.15 2001 315.84 2002 334.67 2003 354.7 2004 375.99 2005 398.64 2006 418.35 2007 439.1 2008 461 2009 484.33 2010 509.23 2011 529.55 2012 551.24 2013 574.69 2014 599.41 2015 625.35 2016 653.22