Year Number of 1990 192675.31 1991 199262.94 1992 207060.78 1993 215794.39 1994 224826.42 1995 234066.9 1996 241907.47 1997 249425.34 1998 256917.47 1999 265065.3 2000 274241.55 2001 277755.61 2002 281785.53 2003 286378.24 2004 291415.15 2005 297001.84 2006 301882.3 2007 307303.87 2008 313699.8 2009 320453.14 2010 327709.07 2011 342949.61 2012 359276.39 2013 376581.32 2014 395088.36 2015 414908.18 2016 435511.4