Hyphens (-) are not used to express a range of values.
Bad Example: from 30-50%
Good Example: from 30 to 50%
(Note that it’s not: from 30% to 50%.)
Of course there are exceptions, as in the case of dates and page numbers:
Good Example: April 29-30, 2010.
Good Example: SPE Reservoir Engineering, Vol. 5, No. 2, pp. 57-63.
Another situation in which we do not use hyphens is a compound modifier when the first word is an adverb that ends in -ly.
Good Example: A well-known man married a full-time employee in an extravagantly decorated hotel ballroom with very rich people attending.
Note that the first two compound modifiers, well-known and full-time, are hyphenated, but the compound modifier with the -ly adverb, extravagantly decorated, is not hyphenated. The same rule applies to the word “very,” as used above.