level raises xp required ACUMEN
10 1               10 40 thornskin & 40 esprit --> so acumen skill = 9 when trained
11 2               14
12 3               20
13 4               28
14 5               39
15 6               55
16 7               78
17 8             110
18 9             155
19 10             217
20 11             306
21 12             431
22 13             607
23 14             855
24 15           1,204
25 16           1,694
26 17           2,386
27 18           3,359
28 19           4,730
29 20           6,660
30 21           9,355
31 22         13,109
32 23         54,308
33 24         58,434
34 25         63,243 methodology:
35 26         71,830 i untrained acumen at the end of a quest.
36 27         84,174 thornskin and esprit were both exactly 40 when I retrained acumen.
37 28       100,788 acumen was at skill 9 after training (but with zero xp expenditures)
38 29       122,574 i immediately raised the skill to 45, and recorded the exp expenditures
39 30       150,798
40 31       187,149 notes:
41 32       224,084 this is a log plot of skill vs. exp
42 33    1,359,539 note the two discontinuities at +23 and +33
43 34    1,428,238 this is definitely not the only exp curve
44 35    1,509,092 skills suspected to use the same curve: at some point(s), the value to raise is identical
45 36    1,673,282 focus the spirit
46 37    1,914,093
47 38    2,237,166
48 39    2,655,582
49 40    3,188,655
50 41    3,862,115