Year	% of total
1990	86.74958425158043
1991	86.342806712168
1992	85.95820153150265
1993	85.60368897333137
1994	70.78363284390457
1995	71.0367990899032
1996	71.29051448107427
1997	71.57113384031422
1998	72.95712984503169
1999	73.16797323586182
2000	73.73897217023888
2001	73.30200098427112
2002	74.30154630078181
2003	74.64654683188226
2004	74.63826148846461
2005	75.4217236969605
2006	74.73308060877797
2007	75.37607631045225
2008	75.55823620563544