# Is the percent symbol okay in this construction?

Direct quote, so I cannot alter.

He said, "We've seen a 10–20 percent a year increase in revenue."

Could the percent symbol work?

He said, "We've seen a 10–20% a year increase in revenue."

Are both good (in your estimation)?

• The en dash is, according to most style guides, required when dealing with numeric intervals; and the per cent sign works just fine (whether or not to add a fine space before it is a matter of style—I personally would, but not all guides agree. Chicago, for one, wants no space and reserves the % sign as more common in scientific and statistical copy). Feb 12, 2014 at 16:53

Yes, this usage of the percent symbol is appropriate. If, however, you are publishing this in a periodical you should check with the relevant style guide and conform to its standards.

• Would hyphens be overkill here? He said, "We've seen a 10–20%-a-year increase in revenue." Feb 28, 2014 at 17:47
• No, they wouldn't be overkill. Different style guides will suggest different specifics and it is always good to compare your usage with whatever your peers are using. Feb 28, 2014 at 19:53

If you are quoting something spoken rather than written, you are free (in the absence of a controlling style guide's specified preference) to use symbols or spelled-out words in situations where they convey the same meaning; but I don't see why you'd want to present readers with a compound phrase that combines an en dash and two hyphens. For immediate clarity of meaning, I would replace the en dash with to and the percentage symbol with percent:

We've seen a 10- to 20-percent-a-year increase in revenue.

The space after "10-" indicates that this term is short for "10-percent-a-year," the hyphens indicate that both the truncated compound and the full compound modify increase, and the space after to follows from and balances with the space after "10-."

It would be equally clear to render this as

We've seen a 10%- to 20%-a-year increase in revenue.

except that (according to your original example) the speaker said "10 to 20 percent," not "10 percent to 20 percent." I wouldn't use the form

We've seen a 10- to 20%-a-year increase in revenue.

because the imperfect parallelism between "10-" and "20%-" bothers me.

Personal preferences aside, Janus Bahs Jacquet and MrHen correctly point out that a publisher will normally specify a general-reference style guide or provide its own house style guide to answer this sort of formatting question.

Actually English style guides (Merriam-Webster guide for writers for example), to be pedantic, recommend that the word percent be used in text (as in your example) reserving the symbol for writing mathematical expressions as in a formula for example. I didn't know this but my 11 year old got into an argument with her math teacher who insisted that the proper way to draw the o/o symbols is with a "script" first o, with a little hat that joins the division symbol (which then I learned is called solidus) and my daughter argued that wasn't needed (as she has seen it in plenty of places written as o/o) so I had to do some research on this. That said, I've read plenty of scientific articles during my PhD, written tons of contract for international energy contracts and the use of the o/o is common use everywhere, so I don't think anybody would care one way or the other.