Forgive me if this isn't the right place, and direct me to the correct place to post.
I've been trying to figure out how to get the yield rates for Mortgage Backed Securities (MBS's) in the United States dating back the last 30 years or so. I've been unable to do so.
The closest I have gotten is the command string
MTGEFNCL F10<GO> to get there. But that's for the historical current coupon (which I understand to be a different thing).
Is there a command or a way to call the data for the yield rates?