Year Number of 1990 3192.79 1991 3280.47 1992 3388.4 1993 3408.83 1994 3537.59 1995 3693.29 1996 3818.88 1997 4040.99 1998 4074.31 1999 4209.43 2000 4396.86 2001 4137.98 2002 4046.6 2003 4007.42 2004 3972.33 2005 3922.46 2006 4024.13 2007 4073.7 2008 4133.21 2009 4260.16 2010 4378.5 2011 4439.7 2012 4476.15 2013 4505.34 2014 4599.04 2015 4705.24 2016 4829.12