Year Number of 1990 187.39 1991 192.13 1992 199.01 1993 203.81 1994 210.52 1995 211.47 1996 215.3 1997 219.28 1998 224.81 1999 231.46 2000 239.14 2001 247.84 2002 254.28 2003 267.42 2004 275.38 2005 279.27 2006 281.79 2007 280.97 2008 295.03 2009 305.02 2010 315.32 2011 326.58 2012 339.41 2013 353.68 2014 369.1 2015 386.49 2016 396.6