Major dictionaries do not agree on the spelling,[1][2][3] giving other options ofper mil,[2]per mill,[1][3]permil,[1][4]permill,[1]permille.[5][6]
The wordpromille is thecognate in Dutch, German, Finnish and Swedish, and is sometimes seen as aloanword in English with the same meaning asper mille.[7][4]
The symbol is included in theGeneral Punctuation block ofUnicode atU+2030‰PER MILLE SIGN.[5] There is also an Arabic-Indic per mille sign atU+0609؉ARABIC-INDIC PER MILLE SIGN.
Promille and permille are likely best known as shorthand terms forBlood Alcohol Concentration, where 1 promille corresponds to 1 gram of alcohol per liter of blood.[8] Promille is used in the legal limits ofblood-alcohol content for driving a road vehicle in some countries: for example: 0.5‰ or 0.8‰.[9]
Cost per mille (CPM), the price of 1000 units, may be used for views of banner and display advertising, and for emails delivered byemail service providers.
In UK insurance usage, the cost per mille is the rate per £1000 of insured value.[10] In India, the premium per mille is the rate expressed as thousandths of the sum assured.[11]
Permille may also be used to express a1000-quantile ("999th permille"),[14][15] but this usage is rare and largely obsolete. Modern publications instead use fractional percentiles ("99.9th percentile").[16]
^Michael W. Sayers; Thomas D. Gillespie; William D.O. Paterson (January 1986)."Directives pour la mesure de l'uni des routes et l'étalonnage des appareils"(PDF) (in French).World Bank. p. 2.L'indice IRI est une mesure de l'uni des routes standardisée, apparentée aux mesures obtenues à l'aide des appareils de type-réponse. Les unités recommandées sont : les mètres par kilomètres (m/km) = millimètres par mètres (mm/m) = pente x 1000.
