Year Number of 1990 282.68 1991 293.83 1992 310.6 1993 325.75 1994 342.49 1995 358.45 1996 372.52 1997 385.08 1998 404.98 1999 413.23 2000 430.04 2001 444.63 2002 460.5 2003 471.32 2004 489.69 2005 526.1 2006 545.27 2007 596.45 2008 633.6 2009 667.51 2010 702.01 2011 732.64 2012 756.4 2013 745.11 2014 748.39 2015 755.97 2016 758.47