group    discolor
                                 1        10.0
                                 1         8.0
                                 1         7.5
                                 1         8.0
                                 1         9.5
                                 1         9.0
                                 1         7.5
                                 1         7.0
                                 2         6.0
                                 2         7.5
                                 2         8.0
                                 2         7.0
                                 2         6.5
                                 2         6.0
                                 2         5.0
                                 2         5.5
                                 3         3.0
                                 3         5.5
                                 3         4.0
                                 3         4.5
                                 3         3.0
                                 3         3.5
                                 3         4.0
                                 3         4.5
                                 4         2.0
                                 4         1.0
                                 4         2.5
                                 4         3.0
                                 4         4.0
                                 4         3.5
                                 4         2.0
                                 4         2.0