I'm guessing the severity of the sentence though was based on the fact the FBI could never figure out the whole picture, as it seems long for a situation where it was never shown that the information was shared with anyone.
Unlike with the Trump case where it is claimed he showed some of the documents to friends and associates. So, if Trump does get convicted I'm sure cases like the one above will be cited to try and increase the severity of his sentence. It would be unreal to see a former President in a federal prison camp.