Year % of total 1990 8.295196236051156 1991 8.427763657140813 1992 8.518639396259406 1993 8.644293960811055 1994 8.583428878577259 1995 8.965537295064738 1996 8.993343711484552 1997 9.305455468374427 1998 10.266072740879263 1999 10.247008203388672 2000 10.420303316172767 2001 10.418634180605046 2002 10.312359229964663 2003 10.626034615938993 2004 10.698745215227266 2005 11.013711160614 2006 11.572033330526953 2007 11.564766006962483 2008 12.275484523310402