Year Number of 1990 2256.5 1991 2304.23 1992 2313.09 1993 2336.02 1994 2364.82 1995 2399.22 1996 2424.24 1997 2467.86 1998 2509.56 1999 2540.52 2000 2566.75 2001 2590.77 2002 2636.89 2003 2649.06 2004 2643.55 2005 2621.8 2006 2599.67 2007 2576.02 2008 2579.74 2009 2596.93 2010 2582.63 2011 2537.94 2012 2517.86 2013 2488.11 2014 2452.25 2015 2418.46 2016 2466.65