3.4 per 1000 words: minimum Pickwick Papers 0.5 – maximum misc Linguistics papers  9.4
1.2% of all punctuation marks
see Punctuation Frequency page for details
In COCA 1,360,298/425 million = 3.2 per thousand
         

1748 J. Mason A Comma Stops the Voice while we may privately tell one, a Semi Colon two; a Colon three: and a Period four.

Here is a lesson in creative writing. First rule: Do not use semicolons. They are transvestite hermaphrodites representing absolutely nothing. All they do is show you've been to college. Kurt Vonnegut, A Man without a Country

KJVI And God said, Let there be light: and there was light.

KJVI And God saw the light, that it was good: and God divided the light from the darkness.

BBC It also made recommendations about:
      Charges - which it claimed were too opaque. It said bigger, lower-cost pension schemes            
       should be able to operate

DB Fact: The Priory of Sion – A European secret society founded in 1099 – is a real organisation

NYT High-end consumers and the people racing for the Black Friday special on $9.44 blenders at Wal-Mart continue to have at least one thing in common: they know hot holiday products go quickly.

CEFR CEF serves the overall aim of the Council of Europe as defined in Recommendations R (82) 18 and R (98) 6 of the Committee of Ministers: ‘to achieve greater unity among its members’ and to pursue this aim ‘by the adoption of common action in the cultural field’.

Type 2 colon

DB Louvre Museum, Paris 10:46pm

NYT Deuteronomy 20:16

CEFR Finnish Nine Level Scale of Language Proficiency 1993: Level 2

Type 3 colon

BBC Altmann, director general of Saga, said: "We need to reform …

Odd uses: IPA, computer languages

OED Definition

 1. In Ancient Greek Rhetoric and Ancient Greek Prosody, a member or section of a sentence or rhythmical period; hence in Palaeogr., a clause or group of clauses written as a line, or taken as a standard of measure in ancient MSS. or texts. pl. cola.

 2. A punctuation-mark consisting of two dots placed one above the other [:] usually indicating a discontinuity of grammatical construction greater than that marked by the semicolon, but less than that marked by the period. pl. colons.

Its best defined use is to separate clauses which are grammatically independent and discontinuous, but between which there is an apposition or similar relation of sense. Thus it may introduce an antithetic statement, an illustration, extract, etc. But ‘its use is not very exactly fixed; it was used before punctuation was refined, to mark almost any sense less than a period’ (Johnson). It is also employed to divide prose into metrical periods for chanting.