Year Number of 1990 294.77 1991 309.54 1992 326.66 1993 345.72 1994 365.64 1995 384.87 1996 402.4 1997 418.63 1998 435.09 1999 454.28 2000 473.4 2001 490.11 2002 505.7 2003 522.41 2004 541.32 2005 560.54 2006 577.5 2007 591.64 2008 604.73 2009 616.1 2010 627.78 2011 642.29 2012 661.98 2013 684.07 2014 707.11 2015 729.86 2016 754.88