What number would you give someone who wants a concrete target number for API code coverage?

UPDATE: To clarify, statement/line code coverage. I realize concrete numbers don't make much sense, but this is for the situation where you tell people that concrete numbers don't make much sense and they still insist on getting a number from you no matter what. I specifically wrote API/SDK because some people might find lower code coverages more acceptable for application/GUI level software, as opposed to libraries, where more interfaces are exposed.