Year Number of 1990 370.36 1991 376.6 1992 386.34 1993 398.7 1994 412 1995 425.74 1996 436.8 1997 447.79 1998 459.32 1999 471.49 2000 485.03 2001 494.32 2002 504.75 2003 516.44 2004 528.7 2005 541.8 2006 555.63 2007 569.73 2008 585.59 2009 602.23 2010 620.15 2011 639.18 2012 659.73 2013 681.23 2014 703.93 2015 727.83 2016 752.99