Sever Oraz writes:
Apologies, I should have included a reference to FS#49104 [1]. As you both
have suggested, it is used in some locales, but more generally, by
adherents to the SI [2] and to the ISO 31-0 [4], which include the
scientific and engineering communities even in English speaking countries.
...but it's extremely rare to see it outside of contexts which care about this
standard :-)
It is possibly a good idea to insert this space conditionally if the locale
in use specifies adherence to the SI; however, since there doesn't seem to
be a universally followed rule regarding this topic [3], it may be also be
a good idea to default to a well-defined and widely-followed norm where
this is regulated, such as the SI brochure and ISO 31-0. Let me know what
you think is best.
I am against it, at least for LANG=C or LANG=en*. It's extremely rare to
intentionally space the percent sign like this like this in these kinds of
user-facing application contexts in English, regardless of what some standard
says.
As some anecdotes:
- English Wikipedia, no space:
https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Percentages
- NASA, no space: https://climate.nasa.gov/scientific-consensus/
- Royal Society, no space:
https://royalsociety.org/topics-policy/projects/uk-research-and-european-union/role-of-eu-researcher-collaboration-and-mobility/snapshot-of-the-UK-research-workforce/
We do not use the spaced percent in contexts like this whatsoever, so what some
standard says is meaningless. What's normal is descriptive, not prescriptive.
