Biotech Values

[iwfal]

With a little effort, you should be able to answer your question—at least for the period from 1993 to the present.

You could have just said either "I don't know" or "it hasn't happened". I was asking hoping to bypass the 10 hours of work it would take to do it myself.

My guess is that it is an extremely rare event - in the 1 in 20 or less class - just as it is for other ACs.