Year Number of 1990 3159.02 1991 3281.56 1992 3404.69 1993 3501.41 1994 3612.99 1995 3737.51 1996 3720.09 1997 3710.22 1998 3697.76 1999 3677.44 2000 3657.73 2001 3710.17 2002 3764.62 2003 3824.23 2004 3875.42 2005 3942.37 2006 4011.11 2007 4087.05 2008 4162.54 2009 4242.08 2010 4333.71 2011 4446.4 2012 4568.73 2013 4682.84 2014 4798.04 2015 4974.97 2016 5179.55