How to reference data someone told me in person?
The conventional way to attribute such information in your references is to cite your source as "So-and-so" (i.e. the person's name) -- "personal communication".   Of course you should get the person's permission to reference them, ideally in an email or some other written format, to be sure that there will be no miscommunication about them having given permission for you to reference them and the numbers they told you. HTH.