Year	% of total
1990	84.55416968019667
1991	84.17084991730596
1992	84.4486429199801
1993	84.50800472551667
1994	84.67278441944353
1995	83.56456259955269
1996	82.42364010426024
1997	82.66003237610155
1998	82.48182148214848
1999	82.02867174361185
2000	81.26418885442642
2001	81.09074343794344
2002	81.51630912198499
2003	80.97960596868938
2004	80.21013167867387
2005	79.51240640926915
2006	79.06652237173823
2007	78.40218737582956
2008	79.56024547906691