Simultaneously, if you hire human translators, you are likely to get machine translations. Maybe not often or overtly, but the translation industry has not been healthy for a while.
The industry is sick because everyone is looking for the lowest prices, but translators don't like machine translation. They don't want to just review the output, because actually doing the translation leads to better understanding of what they have to do.
A machine translation might be useful just to get a bulk-mode translation of unfamiliar words and possibly idioms too. But then it's time for humans.
I would expect there not to be a meaningful number of "unfamiliar words and idioms" to a professional translator.
I would expect that many professional translators have native fluency in only one language.