These graphs are called CDFs, or cumulative distribution function graphs. (Strictly speaking they are empirical CDFs or ECDFs.) The X axis shows the range of grades. The Y axis value for a given grade G shows the percentage of students that had grade <= G. CDFs are super useful, please try to get comfortable with them!
| A range | B range | C range | D | F |
| 17 | 17 | 15 | 4 | 6 |