Year Number of 1990 370.17 1991 383.75 1992 398.11 1993 413.37 1994 430.23 1995 448.92 1996 465.42 1997 483.13 1998 501.71 1999 522.29 2000 544.92 2001 559.75 2002 574.71 2003 588.83 2004 605.53 2005 624.16 2006 633.92 2007 643.19 2008 652.54 2009 662.67 2010 673.29 2011 699.65 2012 727.84 2013 757.18 2014 788.56 2015 823.22 2016 859.84