Year	% of total
1990	78.0946881632865
1991	77.61020108700855
1992	77.35794846375546
1993	76.94388288371516
1994	76.67770836246348
1995	76.6817070015225
1996	75.84759693473798
1997	75.2859639093821
1998	75.26544925209144
1999	74.94940630666522
2000	74.47370508290084
2001	73.25399655250642
2002	72.97784851740884
2003	72.62149969257925
2004	71.84296687006798
2005	71.62017712636363
2006	70.69333405276085
2007	70.42102188900161
2008	70.08889080634808