Year Number of 1990 183.29 1991 189.86 1992 196.67 1993 203.96 1994 211.68 1995 220.52 1996 222.49 1997 216 1998 214.72 1999 216.3 2000 220.26 2001 226.1 2002 232.79 2003 242.72 2004 254.09 2005 265.35 2006 278.51 2007 290.8 2008 303.22 2009 317.68 2010 328.44 2011 338.13 2012 349.36 2013 360.65 2014 372.42 2015 385.29 2016 397.7