Year Number of 1990 309.49 1991 315.96 1992 331.72 1993 347.9 1994 379.6 1995 432.36 1996 422.63 1997 424.89 1998 424.1 1999 417.33 2000 421.36 2001 415.23 2002 410.53 2003 401.1 2004 399.45 2005 397.05 2006 397.41 2007 395.09 2008 392.49 2009 389.95 2010 396.51 2011 400.94 2012 408.05 2013 413.6 2014 419.99 2015 426.95 2016 435.53