The formula used to scale the grades was:

Here's a histogram of scaled scores:

Here are the scaled scores:

``` raw       scaled      grade

100	   100.0        A
99	    99.25
98	    98.5
97	    97.75
96	    97.0
95	    96.25
93	    94.75
92	    94.0
91	    93.25
90	    92.5
89	    91.75
88	    91.0
87	    90.25
86	    89.5        A-
85	    88.75
84	    88.0
83	    87.25
82	    86.5        B+
81	    85.75
85	    88.75
80	    85.0
79	    84.25
78	    83.5
77	    82.75       B
76	    82.0
75	    81.25
74	    80.5
73	    79.75
72	    79.0
71	    78.25       B-
70	    77.5
69	    76.75
68	    76.0
67	    75.25
66	    74.5        C+
65	    73.75
64	    73.0
63	    72.25
62	    71.5
61	    70.75       C
60	    70.0
59	    69.25
58	    68.5
57	    67.75
56	    67.0
55	    66.25       C-
54	    65.5
53	    64.75
52	    64.0
51	    63.25
50	    62.5	D+
49	    61.75
48	    61.0
47	    60.25
46	    59.5
45	    58.75       D
44	    58.0
43	    57.25
42	    56.5
41	    55.75
40	    55.0
39	    53.625      F
38	    52.25
37	    50.875
36	    49.5
35	    48.125
34	    46.75
33	    45.375
32	    44.0
31	    42.625
30	    41.25
29	    39.875
27	    37.125
26	    35.75
25	    34.375
23	    31.625
22	    30.25
20	    27.5
12	    16.5
9	    12.375
6	     8.25
```