I'd be reluctant to even venture a guess on that Tony. :-)
One of our members had a pk of 50 yr old sd and she shared them with several people.
Most reported no germination on
those seeds. The pk contained about 100 sds and at least 1 person reported germination of 2 or 3 sds.
Thats pretty astonishing to get 2 or 3 % on 50 yr old sd. The member lost those seedlings later
I once stored some of the seeds in the freezer and the seed coat just breaks down and the radical emerges a lot quicker after nicking and soaking, even within hours, depending on species, cultivar,or strain! I use and X-acto knife when chipping. A little room for error does not hurt.