Per mille
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A per mille[1][2][3] (from Latin per mīlle, "in each thousand"[4]), also spelled per mil,[4][1][5][6][2][7] per mill,[4][8][5][6][7][9] permil,[4] permill,[4] or permille[3] is a sign indicating parts per thousand. Per mil should not be confused with parts per million (ppm).
The sign is written ‰, which looks like a percent sign (%) with an extra zero in the divisor. It is included in the General Punctuation block of Unicode characters: U+2030 ‰ PER MILLE SIGN (‰).[3] It is accessible in Windows using ALT+0137.
The term occurs so rarely in English that major dictionaries do not agree on the spelling or pronunciation even within a single dialect of English[10] and some major dictionaries such as Macmillan[11] and Longman[12] do not even contain an entry. The term is more common in other European languages where it is used in contexts, such as blood alcohol content, that are usually expressed as a percentage in English-speaking countries.
Examples
Examples of common use include:
- legal limits of blood-alcohol content for driving a road vehicle in some countries: for example: 0.6‰ or 0.2‰.
- seawater salinity: for example: "the average salinity is 35‰".
- tunnel and railway gradients (in some countries in Europe)
- birth and death rates
- baseball batting averages (colloquially)
- property taxation rates: the millage rate (U.S.) or mill rate (Canada)
- expressing stable-isotope ratios - for example: "δ13C was measured at −3.5‰"
- expressing costs for print and online advertisements which are commonly sold at cost per mille (CPM); this is the common unit for all banner and display advertising
- frequently used by email service providers to denominate the cost for 1,000 emails delivered as a cost per mille (CPM)
Related units
- Percentage point
- Percent (%) 1 part in 100
- Basis point (‱) 1 part in 10,000
- Parts-per notation
- Silver fineness (given as "0.000-fine")
References
- ^ a b Cambridge Dictionary Online. "per mille". Cambridge University Press (Cambridge), 2014. Accessed 31 August 2012.
- ^ a b Oxford Dictionaries: The British & World Dictionary. "per mille" Accessed 1 Aug 2014.
- ^ a b c Unicode. "General Punctuation". 2014. Accessed 5 Aug 2014.
- ^ a b c d e Oxford English Dictionary, 3rd ed. "per mil, adv." Oxford University Press (Oxford), 2005.
- ^ a b eReference. "per mil". Houghton Mifflin. Accessed 31 Aug 2012.
- ^ a b Oxford Dictionaries: The American Dictionary. "per mill". Accessed 1 Aug 2014.
- ^ a b Collins English Dictionary. "per mill or per mil". 2014. Accessed 1 Aug 2014.
- ^ Merriam–Webster Online. per mill". Accessed 1 Aug 2014.
- ^ Collins American English Dictionary. "per mill". 2014. Accessed 1 Aug 2014.
- ^ See entries above
- ^ Macmillan Dictionary. "No result". Accessed 1 Aug 2014.
- ^ Longman Dictionary of Contemporary English. "No result". Accessed 1 Aug 2014.