Year	% of total
1990	57.948232456795346
1991	57.19242490468864
1992	56.88410004244851
1993	56.27518226317422
1994	55.9614977059124
1995	55.89919898782421
1996	55.53610657751644
1997	55.332579605543394
1998	55.3804775765726
1999	55.53661794856764
2000	54.96738089464568
2001	54.57851401622809
2002	54.2917593592946
2003	53.989724366966605
2004	53.941542583320626
2005	54.11425032554814
2006	54.17215555433873
2007	54.604154751770636
2008	54.6554144426707