I doubt we'd settle for 10%.
I recognize that the original meaning of decimate was to reduce by 1/10, a punishment applied to mutinous legions in the Roman Army. However, most usage experts have long accepted a broader meaning of decimate: to destroy or kill a large part of a population or group. I do not like it's usage when referring to things other than populations of people or animals.
Usage beyond the original meaning dates back for at least 300 years.