Per mille

[5][6] The word promille is the cognate in Dutch, German, Finnish and Swedish, and is sometimes seen as a loanword in English with the same meaning as per mille.

[7][4] The symbol is included in the General Punctuation block of Unicode at U+2030 ‰ PER MILLE SIGN.

[8] Promille is used in the legal limits of blood-alcohol content for driving a road vehicle in some countries: for example: 0.5‰ or 0.8‰.

[10] In India, the premium per mille is the rate expressed as thousandths of the sum assured.

[11] Gradients (in some countries in Europe) may be expressed as mm/m or m/km, and written with the per mille symbol.

A railroad distance and gradient sign in Gdańsk, Poland. The 50‰ grade is equivalent to 5%.
A tram and gradient sign in Gdańsk, Poland . The 50‰ grade is equivalent to 50 m/km or 5%.
Visualisation of 1%, 1‰, 1‱, 1 pcm and 1 ppm as fractions of the large block (larger version)