Year Number of 1990 377.21 1991 386.5 1992 394.79 1993 400.07 1994 406.37 1995 417.84 1996 430.28 1997 420.72 1998 426.83 1999 433.44 2000 439.12 2001 454.27 2002 463.23 2003 478.89 2004 489.73 2005 502.09 2006 522.33 2007 543.48 2008 568.52 2009 592.45 2010 618.24 2011 655.24 2012 699.32 2013 744.35 2014 794.67 2015 851.11 2016 906.98