Midterm Histogram, 
_suggested_ grade equivalents

13: XX
14:
15: X
16: X
17: XX
18:
19: X             C
20:
21:         -----------------
22:
23:
24: XX
25:
26: XXX           B
27:         -----------------
28: X     
29: XX          A-/B+
30: XX      
31: XX      -----------------
32: XXXX          A
33: X
34:
35: X
36:
37:
38: X
39:
40: