Year % of total 1990 9.541925136951733 1991 9.48207377612224 1992 9.358877257482291 1993 9.517566962171198 1994 9.283495330296038 1995 8.777124487356746 1996 8.586698272020948 1997 9.08884823822909 1998 8.945748516402695 1999 8.67190165547585 2000 8.790145779145819 2001 8.754211894715631 2002 8.640835750893638 2003 9.092345076996518 2004 8.623427853388426 2005 8.896098824172938 2006 8.675446290887573 2007 8.870361869528802 2008 9.143456550169983