Year Number of 1990 2176.57 1991 2223.94 1992 2255.84 1993 2279.62 1994 2313.98 1995 2339.24 1996 2367.83 1997 2369.43 1998 2392.11 1999 2421.18 2000 2445.76 2001 2433.79 2002 2423.2 2003 2439.64 2004 2450.45 2005 2465.03 2006 2476.7 2007 2467.68 2008 2468.41 2009 2464.49 2010 2466.89 2011 2438.5 2012 2428.5 2013 2416.08 2014 2422.25 2015 2443.52 2016 2462.69