Distribution of slopes for the primitive asteroids in our sample (upper panel) and those classified by Tholen (1984) (bottom). Vertical lines indicate the computed median for each taxonomical class. The title of each column indicates the total number of asteroids with such difference computed. B- and T-types have less than five members with computed s1, thus, we decided not to show them in the (s1 − s2) plot. The rightest column does have not a shared x-axis as the general (s3 − s4) distribution is much wider than the classified ones.