The phrase per mille (from Latin per mīlle 'in each thousand')[1] indicates parts per thousand.[2] The associated symbol is ‰, similar to a per cent sign % but with an extra zero in the divisor.
| ‰ | |
|---|---|
Per mille | |
| In Unicode | U+2030 ‰ PER MILLE SIGN (‰) |
| Related | |
| See also | U+0025 % PERCENT SIGN U+2031 ‱ PER TEN THOUSAND SIGN (Basis point) |
Major dictionaries do not agree on the spelling,[1][2][3] giving other options of per mil,[2] per mill,[1][3] permil,[1][4] permill,[1] permille.[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]
Computer systems
editThe code point for the glyph is included in the General Punctuation block of Unicode characters: U+2030 ‰ PER MILLE SIGN.[5] It may be typed using Alt+0137, Compose%o,[a] Ctrl+⇧ Shift+u 2030, or ⌥ Option+⇧ Shift+r according to operating system.
Examples
editBlood alcohol concentration
editPromille and permille are likely best known as shorthand terms for Blood Alcohol Concentration, where 1 promille corresponds to 1 gram of alcohol per liter of blood.[9] 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]
Cost per mille
editSales and marketing
editCost per mille (CPM), the price of 1000 units, may be used for views of banner and display advertising, and for emails delivered by email service providers.
Insurance
editIn UK insurance usage, the cost per mille is the rate per £1000 of insured value.[11] In India, the premium per mille is the rate expressed as thousandths of the sum assured.[12]
Gradients
edit
Gradients (in some countries in Europe) may be expressed as mm/m or m/km, and written with the per mille symbol.[13][14]
Isotope ratios
editPer mille may be used to express stable-isotope ratios—for example: "δ13C was measured at −3.5‰"
Taxation
editCharity fraction
editIn Italy, it is possible to nominate a charity or charities to receive "five per mille" (5‰) of personal taxation payments.[15]
Property tax
editProperty taxation rates may be expressed as the millage rate (U.S.) or mill rate (Canada), from mill (currency), one thousandth of a dollar.
Quantile
editPermille may also be used to express a 1000-quantile ("999th permille"),[16][17] but this usage is rare and largely obsolete. Modern publications instead use fractional percentiles ("99.9th percentile").[18]
Salinity
editSeawater salinity is often expressed per mille. Average marine salinity is about 35 parts per thousand or 35‰ (3.5%).[19]
Related units
edit
- Percentage point difference of 1 part in 100
- Percentage (%) 1 part in 100
- Basis point (bp) difference of 1 part in 10,000
- Permyriad (‱) 1 part in 10,000
- Per cent mille (pcm) 1 part in 100,000
See also
edit- Parts-per notation
- Per-unit system
- Percentile
- Fineness of precious metals (given as "0.000-fine")
