Year Number of 1990 3425.31 1991 3516.46 1992 3618.85 1993 3730.55 1994 3849.38 1995 3976.97 1996 4099.11 1997 4225.18 1998 4358.42 1999 4502.22 2000 4661 2001 4864.86 2002 5087.98 2003 5334.07 2004 5605.13 2005 5907.55 2006 6204.93 2007 6531.68 2008 6893.49 2009 7281.01 2010 7696.03 2011 7859.29 2012 8017.94 2013 8172.71 2014 8346.17 2015 8546.69 2016 8713.66