In technical documentation I often see a use of per which I believe is wrong. The example would look like this: The following table shows a number of users in our company per operating system. Then follows a two column table with operating system names in the first column and numbers (of users) in the second one, say Windows - 25, MacOS - 15, Linux - 5, etc.
Dictionaries that I checked (Longman, Cambridge, Oxford, Macmillan) say that per can be used to express rates, prices, measurements and is synonymous to for each. Indeed, if you replace per in my example with for each everything gets better: clear, grammatically correct and unambiguous. With such a use of for each I fully agree. However, I think that use of per is incorrect in my example.
I will express my arguments in a more formal way. I think that a phrase A for each B can have two slightly different meanings:
- A, seen as some resource, is spread somehow between some number of B, which is countable or uncountable. For the speaker a "personality" of each element in B is irrelevant, they are indistinguishable. The only thing which matters is the average spread of resource A over B.
- A is seen as some property of B. All elements in B are clearly distinguishable. B can be countable (then relation between A and B can be shown in a table) or uncountable (then the relation between A and B cannot be fully shown in a table, only some samples can be presented this way, however, some other ways, e.g. graphs, formulas, etc. could be used). "Personality" of each B is really important for the speaker, taking average values is not appropriate (that is why a table with detailed listing follows).
I believe that replacing for each with per is only valid for the case 1, but is incorrect in the case 2. All the mentioned dictionaries have examples that fall into case 1. The dictionaries have neither detailed explanations nor examples of incorrect use (case 2).
I am not a native English speaker. In my native language (Russian) there is a clear differentiation between cases 1 and 2: for the case 1 some fixed prepositions are used (similar to per) , in the case 2 other constructs are used (something like for each, of each, etc. or cases like genitive). You can use constructs from the case 2 in the case 1, but not vice versa. People that construct sentences like in the example are also not native English speakers, they speak German. I know that German has similar words per/pro which come from the same Latin origin as English per. It could be that this per/pro is a false friend. Unfortunately, my knowledge of German is not sufficient to comment on valid uses of per/pro.
Since both sides are not native English speakers I need to find an authoritative source of information to support my opinion or convince myself that I am wrong. Of course, if native speakers do mistakes as well, this does not count. I am only interested in the normative use.
