I believe I used a fairly small number for civilizational collapse and extinction, on the order of ten to fifteen percent. I just don't find such doomsday scenarios that likely or plausible.
It may be that my background and upbringing have inured me to it - I've seen the end of the world not happen far too many times in my lifetime:
There's probably more if I stop to think about it.
At the moment, I find biotech to be the most likely existential threat, with general civilization collapse and strong AI the next two major candidates.
I wrote an article about the process of signing up for cryo since I couldn't find any such accounts online. If you have questions about the sign-up process, just ask.
A few months ago, I signed up for Alcor's brain-only cryopreservation. The entire process took me 11 weeks from the day I started till the day I received my medical bracelet (the thing that’ll let paramedics know that your dead body should be handled by Alcor). I paid them $90 for the application fee. From now on, every year I’ll pay $530 for Alcor membership fees, and also pay $275 for my separately purchased life insurance.
http://specterdefied.blogspot.com/2015/04/how-to-sign-up-for-alcor-cryo.html