Year Number of 1990 254.94 1991 260.47 1992 266.66 1993 273.32 1994 280.54 1995 288.57 1996 290.24 1997 292.62 1998 295.46 1999 298.86 2000 303.08 2001 303.56 2002 304.87 2003 306.78 2004 309.32 2005 312.79 2006 318.01 2007 323.53 2008 329.99 2009 337.05 2010 345.05 2011 351.89 2012 359.71 2013 368.05 2014 377.06 2015 386.75 2016 396.99