Year	% of total
1990	89.06902994578175
1991	88.71609201070684
1992	88.49795514431385
1993	88.25868557672517
1994	87.9333316595317
1995	87.86310093686357
1996	87.98188117818785
1997	87.6543384900842
1998	87.21347678791034
1999	87.21417140600859
2000	87.44850767603667
2001	87.87753352039262
2002	87.38209351171176
2003	84.85755109610425
2004	84.7433915879752
2005	84.77230221190453
2006	85.77132629612062
2007	83.86950890976976
2008	86.20320276137788