How to obtain a percentile ranking for a journal? (i.e., top 30%; 30% to 50%) My institution ranks scientific achievement according to some criteria when evaluating promotions, positions, etc. for its subjects (students, grad students, personnel, etc.) This is done by a rule book that is specified in the form of a bylaw and is administered by the ministry of science, therefore it is not local to my institution, but applied nationwide.
The passage about SCI journal publications states that journals are divided into three groups:


eminent international journals - a journal that in its subject ranks in the top 30% journals in ISI list publications
outstanding international journals - the same but for &lt;30% and >50%
international journals - the same for &lt;50%


The difference in "points" awarded for publications in each of the categories is rather large. I was wondering how I could determine which journals fall into a criterium from above?

I talked to the administrative service, but got no satisfying answer, i.e. there is no list of journals (which is understandable, as there are far too many subjects). They told me something along the lines: "These things will be evaluated when the time comes", which is, of course, not at least satisfactory to me.
I talked also briefly with the head of the department and he told me that he never really gave it much thought, I should publish in journals that suit me, the higher the impact factor and prestige the better of course, but in the end it isn't that much of an imperative, and that I should let the "politicians" and administrators worry about those tiny matters. I would, however, still like to know which journals I should favorite.

PS: the rule book naturally specifies similar criteria for various scientific publications (conferences, patents, books, etc.), but since I'm working on my first article to be submitted to a journal and I still haven't decided which journal, I would like to take things like this into account
Likely this is not the answer you want to hear, but I assume the administrative service you talked to is correct. If nobody really knows which journals fall under which of these (rather subjective) categories, it will not be feasible to in advance establish for sure way how much any paper you write will count in the end, when you are evaluated.

This is not nearly as strange as it sounds. Formal rules for promotion and the evaluation of research tend to live in the ugly grey area between bureaucrats who like things orderly, well-defined and, most importantly, written down, and the reality of science, where basically no two scientists will ever be able to agree on an absolutely consistent quality ranking of publication outlets. What usually happens is that some sort of nebulous rankings are defined without specifically ranking concrete venues,and then leave it to a commission of academics to decide ad hoc which publications fall into which category.

At my current university, we have similar nebulous requirements for PhD graduation. Essentially, it is required that students need at least one A-ranked publication. However, what is considered A-ranked varies considerably between different faculty, and is basically negotiated when graduation time is near. I assume requirements for tenure etc. are handled similarly.

Note that there are some initiatives that are trying to rank publication venues more formally, for instance CORE for computer science. However, these rankings are also far from perfect (or, for some fields, they are apparently downright terrible).