Year Number of 1990 40639.32 1991 43216.1 1992 46043.44 1993 48782.44 1994 52120.44 1995 55942.48 1996 55635.78 1997 55407.55 1998 55215.33 1999 55016.9 2000 54850.83 2001 56291.22 2002 57692.1 2003 59339.46 2004 60869.01 2005 62529.69 2006 62341.16 2007 62162.49 2008 62002.57 2009 61920.97 2010 61936.22 2011 62125.99 2012 62346.42 2013 62621.15 2014 62944.7 2015 63787.12 2016 64797.02