Year Number of 1990 196.19 1991 209.65 1992 226.39 1993 239.7 1994 255.08 1995 264.07 1996 274.79 1997 283.05 1998 281.44 1999 281.06 2000 279.74 2001 279.52 2002 286.1 2003 293.57 2004 296.18 2005 300.86 2006 303.84 2007 305.42 2008 308.81 2009 307.59 2010 309.41 2011 308.23 2012 314.52 2013 326.07 2014 333.85 2015 340.73 2016 348.2