The following is a
non-confirmed quote from eaglejarl on the discord about ninja demographics that he wants checked for plausibility:
Now, as a recap, Konoha in a 'stable state' (i.e. before the USoUD and BotG) has about 1200 Genin, 250 Chuunin, and 50 Jounin. Okay, let's go.
Genin:
Genin have a fairly even death rate here, let's average that out and say that a Genin lives from 12 to 17, five years. This means that 240 Genin die, get promoted, or go missing a year and 240 Genin graduate from the Academy each year.
Chuunin:
Chuunin can be put in two groups: doomed Chuunin and Jounin-track Chuunin. Doomed Chuunin die in less than a year, let's round that off to a flat year for simplicity. Jounin-track Chuunin stay Chuunin for about six years before becoming Jounin. This means that for every year of Doomed Chuunin there are six years of Jounin-track Chuunin to work with.
There are 250 Chuunin in Konoha. If 2/3 of new Chuunin are doomed Chuunin, then there are (1/3 * 6) = 2 years of Chuunin, 3 times as many Jounin-track Chuunin as doomed Chuunin walking around at a given moment. That means there are about 190 Jounin-track Chuunin and about 60 doomed Chuunin in Konoha.
This amounts to a draw of about 90 Genin a year, meaning that of the 240 Genin that graduate from the Academy, about 150 will die as Genin, about 60 will die as doomed Chuunin, and about 30 will likely hit Jounin.
Jounin:
There are
three categories for Jounin here: doomed Jounin, regular Jounin, and S-track Jounin. Doomed Jounin die within the first year, and the regular Jounin population die within five years (let's say an average of 3), leaving only the S-track Jounin alive beyond that.
There are 50 Jounin in Leaf in a stable state. That means that there's one year of doomed Jounin, three years of regular Jounin, and something like thirty years of S-rank Jounin that together equal 50.
Starting from the S-rankers, let's make a generous estimate that Konoha averages about 5 S-rankers normally. That drops our Jounin pool down to 45 between the doomed and regular Jounin.
At a draw of 30 new Jounin per year,
n of them are doomed Jounin and
m of them are regular Jounin. With a total non-S-track Jounin population of about 45, we get the following equations:
n + 3m = 45 and
n + m = 30. Rearrange for
n = 30 - m and substitute as
(30 - m) + 3m = 45 and solve for
m = 7.5. Round that off and we can conclude that of the 30 new Jounin Leaf gets each year, 22 of them are doomed Jounin and 8 of them are Regular Jounin. Or, in other words, 73% of Jounin die in their first year and 27% die within five years.
(S-rankers have been omitted from these calculations because 5 S-rankers at 30 years per S-ranker is one S-ranker every six years, a rounding error of the Jounin population).
In Conclusion:
Taking the
not confirmed numbers eaglejarl provided on discord and making a few small assumptions to extrapolate from them:
- The Academy class size is something like 240 Genin a year.
- About 150 of those Genin (63%) will die as a Genin, and the other 90 will be promoted to Chuunin.
- About 60 of those Chuunin (67%) will die within a year, and the other 30 will be promoted to Jounin.
- About 22 of those Jounin (73%) will die within a year, and the rest will die within five years.
- S-rankers are a rounding error.
edit: math error in Chuunin calcs.
edit2: improved Jounin model and fixed calcs.