Year Number of 1990 292.01 1991 308.96 1992 326.36 1993 344.56 1994 364.7 1995 387.32 1996 398.18 1997 409.89 1998 422.26 1999 435.58 2000 449.97 2001 461.91 2002 474.81 2003 489.55 2004 505.63 2005 523.27 2006 543.3 2007 564.93 2008 588.38 2009 613.79 2010 641.53 2011 664.86 2012 689.61 2013 713.92 2014 739.42 2015 766.3 2016 798.56