Year Number of 1990 24789.46 1991 25136.52 1992 25664.75 1993 25919.32 1994 26328.27 1995 26731.45 1996 27315.85 1997 28017.32 1998 28502.92 1999 28857.05 2000 29269.78 2001 29581.65 2002 29956.13 2003 30164.94 2004 30760.05 2005 31593.68 2006 31532.88 2007 31801.97 2008 32309.04 2009 32635.61 2010 33237.01 2011 33779.24 2012 34060.85 2013 34894.21 2014 35785.77 2015 36534.75 2016 36628.83