[78-L] 78s to 45s switchover dates

[Malcolm]

Is there a list of the approximate dates and/or matrix numbers for
the last 78rpm records released by US record manufacturers? I've
not seen one. We all pretty nuch accept that 1958 marked the
switchover to 45rpm records, and that 78 production continued in
India, Japan and South America (and possibly Canada) for awhile longer,
but has any enterprising researcher made up a list of what I'm seeking?
I am kind of surprised that this wasn't tackled by Galen Gart in his
American Record Label Directory. It seems an obvious addition.
Ah, well.
Malcolm