I can achieve 98.5% accuracy. Is this the data set you are taking about?
@relation wisconsin-breast-cancer
@attribute Clump_Thickness integer [1,10]
@attribute Cell_Size_Uniformity integer [1,10]
@attribute Cell_Shape_Uniformity integer [1,10]
@attribute Marginal_Adhesion integer [1,10]
@attribute Single_Epi_Cell_Size integer [1,10]
@attribute Bare_Nuclei integer [1,10]
@attribute Bland_Chromatin integer [1,10]
@attribute Normal_Nucleoli integer [1,10]
@attribute Mitoses integer [1,10]
@attribute Class { benign, malignant}
@data
5,1,1,1,2,1,3,1,1,benign
5,4,4,5,7,10,3,2,1,benign
3,1,1,1,2,2,3,1,1,benign
6,8,8,1,3,4,3,7,1,benign
4,1,1,3,2,1,3,1,1,benign
8,10,10,8,7,10,9,7,1,malignant
1,1,1,1,2,10,3,1,1,benign
2,1,2,1,2,1,3,1,1,benign
2,1,1,1,2,1,1,1,5,benign
4,2,1,1,2,1,2,1,1,benign
1,1,1,1,1,1,3,1,1,benign
2,1,1,1,2,1,2,1,1,benign
5,3,3,3,2,3,4,4,1,malignant
1,1,1,1,2,3,3,1,1,benign
8,7,5,10,7,9,5,5,4,malignant
7,4,6,4,6,1,4,3,1,malignant
4,1,1,1,2,1,2,1,1,benign