Year	% of total
1990	87.60114623324249
1991	87.11441317262033
1992	86.89275762308779
1993	86.71661090676902
1994	73.69410985870402
1995	74.15403707487084
1996	74.26069192484417
1997	74.7618566361486
1998	75.68819902953744
1999	76.10094690754893
2000	76.50222709035444
2001	76.07342097448843
2002	76.81799825356632
2003	77.24552664991073
2004	77.28698423175202
2005	77.99776888054787
2006	77.54462060868772
2007	77.96373120060778
2008	78.05236906410708