Year	% of total
1990	85.79614770288973
1991	85.40852631469107
1992	84.9913714746083
1993	84.61208785142998
1994	65.11231504178231
1995	65.67612193870869
1996	65.82183877602854
1997	66.38013347315916
1998	68.13316102559664
1999	68.52139426285552
2000	69.22638078829638
2001	68.64545320914547
2002	70.09387089511556
2003	70.80998860554051
2004	70.79641487790407
2005	71.86422031738779
2006	70.98463236954457
2007	71.3623416867861
2008	71.4460815097516