[valerij]

i've picked up this kind of thousand separation at some point to make large numbers scannable. c.f.

    1600000000
    1'600'000'000

separating at 10³ is due to counting customs of the region i live in.

using an apostrophe `U+0027` appears to be the least wrong use of possible glyphs accessible on my keyboard layout

also c++14 does it this way

[jgtrosh]

It's common practice to use commas for this in anglophone countries, but it collisions with french decimal separator; so it's a reasonable choice.