Hyphens are used in written English to join compound adjectives or original compound verb. These can describe periods of time such as age, show range between numbers, and join some prefixes and suffixes to root words.
The correct use of hyphens in English is extensive, and they can often be used in any way to clear up ambiguity. They are generally used when numbers are involved, such as page ranges, ages (a two-year-old boy) and any written numbers from "twenty-one" and above. When used in between non-numerical words, they often make the meaning of the sentence more clear. Without the hyphen in the phrase "stolen-car report," it would be difficult to understand if it were describing a report of a stolen car or a car report that had been stolen.