Year Number of 1990 3385.75 1991 3489.31 1992 3614.78 1993 3803.16 1994 3948.63 1995 4122.95 1996 4303.61 1997 4469.07 1998 4629.96 1999 4700.29 2000 4763.2 2001 4785.19 2002 4806.15 2003 4862.73 2004 4912.28 2005 4984.78 2006 5082.75 2007 5152.96 2008 5099.76 2009 5069.96 2010 5065.8 2011 5157 2012 5174.05 2013 5214.01 2014 5265.24 2015 5408.39 2016 5548.5