Interesting. Like Jayles I'd have guessed that proverb use has been in a steady, sad decline in the last few decades (extensive use of proverbs reminds me of my grandmother's baking), and I'd have been wrong.

You've got to be a bit careful as some proverbs/sayings come to prominence as titles of films, books, TV programmes, etc, and you'll probably get a spike then. E.g. "when the going gets tough" (Billy Ocean, mid-eighties) and "birds of a feather" (Sharon & Tracy, early nineties).

I'm surprised by how new some of these proverbs are. Look at "fat lady sings" on Ngram.
"The apple doesn't fall far from the tree" - that one's been around for ages, but for some reason it seemed to skyrocket between 1980 and 2000. I wonder why.

We use kilometres here in NZ, but people still talk about mileage, just like mara said they do in Canada.
"What's the mileage on that car?"
"Eighty thousand kays."

People also say things like "it's done a lot of kays" but I've never heard (or seen) kilometrage. It's just not a pleasant word to say. For all the advantages of the metric system, I'd say its biggest shortcoming is linguistic: the imperial measurements are nicer and more convenient to talk or write about.

As for fuel economy, the metric equivalent of "miles per gallon" tends to be "litres per 100 km", in NZ at least. That feels weird because it's the inverse, i.e. a low number is good.

Yes people now seem to use "medication", "meds" and "medicine" almost interchangeably. "Medication" (or "meds") tends to be a bit of a euphemism: some people don't like to say they take drugs, tablets or pills. I also think there's a tendency to talk about "medicine" for a drug taken in liquid rather than tablet form.

As for "mentality" in that song, I think you can (and sometimes have to) break the rules in songs so that the lyrics fit.

I don't think I'd ever use it in conversation, polite or impolite. There was however a game show in the UK called Catchword (early nineties?) where you had to make the longest word you could from a given set of letters. This particular F-word came up all the time.

I don't mind the FYI world of electronic communication, but when people say "eff why eye" in conversation and want to touch base with me, that's a whole nother matter.

Off-topic: regarding AFL/NRL finals, they could get around all those terminology issues by just awarding the championship to whichever team gets the most points during the season like they do in football (I'm talking round ball here). The finals system to me is like a marathon where the first eight runners to reach 25 miles start the last mile at the same time.
Talking of octopuses (which is the only acceptable plural to me), how about octo-finals for the round before the quarter-finals?

Nigel_P: yes, pick up any old-ish book published in the UK and it'll be full of recognize, realize, etc. This whole anti-Z thing seems quite recent.

I'd say underexaggeration was something along the lines of:
"His girlfriend looks about twelve!" when she looks more like eighteen, or:
"That painting isn't worth anything" when you could sell it for a few dollars.

I'd say (nought) point two five percent. "Nought" is probably a British thing.

Regarding "point twenty-five", I'm not sure it's wrong (as a couple of you have said). I think it's just the American way of saying it. True, 0.25 has nothing to do with the number 25, but it doesn't have anything to do with the numbers 2 and 5 either.

For me it's pretty clear that "Who knows?" needs a question mark, just as other rhetorical questions like "What's the point?" need one.

As for your longer sentence Dyske, I wouldn't read it like a question (by the time I get to the end of the sentence, my brain has forgotten that it started with a "who") so I'd say a question mark is optional in that case.

MICE!!