Year	% of total
1990	90.19782294187897
1991	89.66556297433696
1992	89.3401794106016
1993	89.01957100415278
1994	69.3505861533288
1995	69.39119605438445
1996	69.57312769969889
1997	69.71431252213581
1998	70.62377776576847
1999	70.66580497352828
2000	70.82485529630611
2001	70.42635848567966
2002	71.48248812198374
2003	71.68403951422019
2004	72.0232920330902
2005	72.7290339501411
2006	72.30929263734109
2007	72.5769290801834
2008	72.69047429110012