Year Number of 1990 207.56 1991 209.56 1992 216.35 1993 221.37 1994 230.21 1995 241.11 1996 251.56 1997 256.36 1998 263.32 1999 267.63 2000 275.17 2001 273.67 2002 280.27 2003 285.19 2004 297.65 2005 310.58 2006 313.09 2007 314.23 2008 318.55 2009 328.95 2010 336.96 2011 347.47 2012 351.57 2013 367.07 2014 373.53 2015 382.76 2016 391.23