Dont get hung up on the %. Our cover pages get covered in Red saying 'you've copied this work'. Well of course I have. It's been in every single assessment I've done, and all the other students in the uni have copied it too. It's only my name and student number that sometimes appear, and it will highlight that I copied the essay title off my classmate.
Luckily, the lecturers ignore this. It's when that a patchwork of colour appears, so you copy/paste from one source, but then use synonyms for every other word that is poor practice and also plagiarism, even with a correct citation and reference.
We get to see our scores in the feedback. It used to be visible in first draft submissions too, but not final versions. Whether a script is kept in Turnitin's database is turn off-able