Year % of total 1990 49.63518227223045 1991 49.60948168123956 1992 49.921724353142736 1993 49.688989960810204 1994 49.930654023754656 1995 50.12671009544457 1996 49.73830274161129 1997 49.198038296637975 1998 49.19416204540221 1999 49.089977263689754 2000 48.54238254721588 2001 48.12875591969779 2002 47.94042838449723 2003 47.29623439127013 2004 47.09727156157852 2005 47.08810727561975 2006 46.463919515865925 2007 45.944307826677715 2008 45.46888155012899