Year % of total 1990 9.822446429359793 1991 10.142720967815482 1992 10.465162965447245 1993 10.668454750354455 1994 9.052392559032059 1995 8.97800429207957 1996 8.873659493232601 1997 8.722762078988696 1998 8.191704526973414 1999 7.886501107474159 2000 7.508299620430935 2001 7.642164248788585 2002 7.391849761428673 2003 7.529529257859612 2004 7.585601028922691 2005 7.482730400234815 2006 7.823648864930458 2007 7.773843112348629 2008 7.883040335109108