In our state, you only have to provide the records you generated. Now, I think that is pretty lame, so we send the whole record. We can also send a summary letter, although I never have as I am sure this would meet with way too many problems. I think that works best with psychiatrists.
Actually, come to think of it, there is no statute requiring one to give any records to anyone after they retire in the state of Maine.
But what works best and what is legally required to provide can be the same thing.