Year	% of total
1990	85.15838846570752
1991	84.91621884666672
1992	84.65584258673928
1993	84.37992300980427
1994	83.55792593837137
1995	84.07789898590548
1996	84.65270952639919
1997	85.33917145249602
1998	86.57887071939919
1999	87.48515610441179
2000	88.4094294529543
2001	88.23674746720317
2002	88.97648945442653
2003	88.83171559710372
2004	88.95732911178716
2005	89.20945739473359
2006	88.58012372399998
2007	88.56027398236378
2008	88.33702199034171