There is no central authority that dictates the use of the English language (that is both descriptive of reality and prescriptive in that I don't think there should be).
Meaning is not purely a matter of emergent use however, it also derives from the meta discussion around that use and the collective attempts to codify use in dictionaries etc.
In this case I'm being prescriptive and saying this is a terrible way to use rate and reflects typical journalistic mathematical illiteracy. Anyone and everyone is however free to ignore my opinion of course.
