2009 is latest reported year. For comparison:

  1992   5.7
  1993   6.2
  1994   6.8
  1995   5.3
  1996   7.5
  1997   7.0
  1998   7.2
  1999   7.2
  2000   7.9
  2001  10.6
  2002  10.7
  2003  10.8
  2004   8.3
  2005   7.5
  2006   8.5
  2007  10.1
  2008  13.1
  2009  16.0