Year Number of 1990 2577.71 1991 2575.71 1992 2570.63 1993 2564.82 1994 2564.68 1995 2572.74 1996 2559.11 1997 2548.59 1998 2540.67 1999 2532.02 2000 2520.89 2001 2495.79 2002 2465.7 2003 2432.08 2004 2413.15 2005 2406.33 2006 2391.63 2007 2375.82 2008 2359.63 2009 2346.92 2010 2338.35 2011 2378.95 2012 2416.75 2013 2453.63 2014 2499.93 2015 2554.63 2016 2611.07