Year	% of total
1990	89.61451825654406
1991	89.43444726623616
1992	90.28717807315883
1993	90.47570023443305
1994	90.9398062806712
1995	90.895177217864
1996	90.52875996475962
1997	90.741830394206
1998	90.17153264910696
1999	90.05377061620699
2000	89.837357094292
2001	90.48580173327178
2002	90.22182445668929
2003	90.5863380048405
2004	90.04744523670655
2005	90.16707908529321
2006	89.71889563459533
2007	91.62763280729602
2008	91.16590146011737