What does the percentage in leader history tab means?

[Henoch]

Hello
I cannot find any information about the strange % number at end of each row in the leaders history tab
It looks like here:
Spent 6XP to improve diplomacy with +1 levels. (14.4%)

So what the 14.4% number means?
I have noticed it usually decreases when leader successfully increased the skill but not always.

You can find the screenshot of what I'm talking about in the current documentation in section:
4.4.8. LEADERS IMPROVE WITH EXPERIENCE

[Soar_Slitherine]

My best guess is that it's the chance of gaining a skill level upon spending a point of XP.

[Henoch]

Thanks for your answer. This was my first thought but statistically there are too many successful skill increases compared to the % so I doubt it is it.
Update: after watching https://youtu.be/J1KDliJEYJk I think the answer above may be correct. The % may be tested more than once depending amount of XP points spent.

I did some research and analyzed my leaders history and I found a pattern:

The % visible in parenthesis is computed based on the Key attribute linked to the skill the leader wants to increase.
So if my leader has INT = 28 and he is trying to learn Agriculture from 0 to 3 the % will be 28 x Multiplier = (22.4%) in this case the Multiplier is 0.8

The multiplier is a dynamic variable different for some skill level ranges so the higher the new learned value of a skill can be the more the multiplier decrease the Attribute so you will see smaller percent numbers

Skill Level range Multiplier
0-4 M=0.8
5-9 M=0.4
10-14 M=0.27
15-19 M=0.2
20-29? M=0.16
30-36? M=0.12
37> ? M=0.1

In last three rows I'm not sure what is the range

So what it means? I think it may reflect how much of the skill levels you can learn. The more you progress in a skill the more you consume the available levels for this skill so at higher levels you mastered the skill so much that there is nothing new to learn. But I'm not sure why it's visible as % then, Maybe it's a chance to to gain +1 level for each portion of XP spent? Hard to say but for sure the calculations are matching logs.

Some examples:
Spent 32 XP to improve Prospecting by +8 levels (11.2%)
He has Prospecting 0 +8 = 8 so M = 0.4
INT 28 x 0.4 = 11.2

Of course I may be guessing here

Regards