Likelihood of MBTI types becoming managers

I’ve been reading the book ‘[YOU – Being More Effective In Your MBTI Type](’. The book indicates the percentage of the population with each MBTI type, as well as the percentage of managers represented by each MBTI type.
So I put two and two together, and came up with a ratio (% managers to % population).

From the list, you may notice:
8 of the 16 MBTI types have a higher ‘likelihood’ of being managers (which I’ve coloured in green):
1. 6 out of these 8 are Intuitive (N)
2. 6 out of these 8 are Thinking (T)
3. 6 out of these 8 are Judging (J)
4. It doesn’t seem to matter if you are Introvert (I) or Extrovert (E) as they are equally represented
5. The ‘best’ categories are the NTJs followed by the NTPs, the STJs and finally the NFJs.
6. Extroverts tend to do better than their Introvert equivalents, but the difference isn’t significant – they’re always paired together according to the ratio I’ve calculated
So I deduce that managers – at least according to the authors’ definition – tend to be big picture, thinking rather than feeling, and decisive – taking the lead. However I believe one must strike a balance. Even if we’re big picture, we shouldn’t be sloppy about important details. Even if we’re analytical about things, we shouldn’t forget about people. And even if we like structure, we have to accept the fact that nothing in life is 100% assured so we have to be open to changes too.
Of course, my analysis comes with a disclaimer:
1. I am not a certified MBTI professional
2. This data is based on US figures, 1998
3. Not everyone wants to become a manager and just because your MBTI type is less likely destined for managerial roles, doesn’t make you less worthy as a human being
4. It’s unclear whether these people are actually ‘good’ managers or not, as that would be a subjective assessment
5. Your own MBTI type can change over time, so nothing is cast in stone
As someone who took the official MBTI test and scored EN(FT)J (50%F, 50%T), I welcome constructive comments on my analysis.