Year Number of 1990 376.97 1991 385.84 1992 395.69 1993 406.24 1994 417.66 1995 429.81 1996 440.53 1997 451.02 1998 461.54 1999 471.78 2000 481.93 2001 489.59 2002 497.19 2003 506.69 2004 516.16 2005 525.9 2006 535.96 2007 546.5 2008 558.5 2009 572.35 2010 588.34 2011 617.49 2012 649.83 2013 683.37 2014 718.14 2015 753.95 2016 792.43