English style guides prescribe writing the percent sign following the number without any space between (e.g.
[25] The letter p with its descender crossed by a horizontal or diagonal stroke (to indicate abbreviation) conventionally stood for per, por, par, or pur in Medieval and Renaissance palaeography.
[26] At some point, a scribe used the abbreviation pc with a tiny loop or circle (depicting the ending -o used in Italian ordinals, as in primo, secondo; it is analogous to the English -th as in 25th).
[27] The pc with a loop eventually evolved into a horizontal fraction sign by 1650 (see below for an example in a 1684 text)[29] and thereafter lost the per.
In SQL, the percent sign is a wildcard character in "LIKE" expressions, for example SELECT * FROM table WHERE fullname LIKE 'Lisa %' will fetch all records whose names start with "Lisa ".
In TeX (and therefore also in LaTeX) and PostScript, and in GNU Octave and MATLAB,[33] a % denotes a line comment.
In linguistics, the percent sign is prepended to an example sentence or other string to show that it is judged well-formed (grammatical) by some speakers and ill-formed by others.