The historical hip hop presence metric shows the effective chart share occupied by hip hop artists. “Effective chart share” is calculated by assigning song scores that are inversely correlated with song rank (i.e. score of 100 for rank 1, score of 99 for rank 2, and so on) and then calculating a total score for hip hop artists as a percentage of the highest score possible. Numbers closer to 100 indicate a larger hip hop presence and numbers closer to 0 indicate a smaller hip hop presence. Note that for these purposes “hip hop” includes not only hip hop as narrowly defined but also rap and R&B.