Year Number of 1990 406.57 1991 427.4 1992 439.41 1993 444.69 1994 466.08 1995 451.97 1996 430.58 1997 402.08 1998 424.38 1999 415.29 2000 437.01 2001 455.2 2002 479.63 2003 515.73 2004 555.47 2005 584.92 2006 625.88 2007 664.94 2008 680.11 2009 705.64 2010 728.81 2011 747.15 2012 761.12 2013 770.11 2014 803.26 2015 829.48 2016 858.17