"One of my books mentioned that Cosmic rays go up to 1000 MeV in energy. I thought those were the most common with energies dropping to a minimum of 100 MeV based on text, but I'm not sure after seeing this table list only the lower end."

I spent about an hour trying to get an answer, but can't say I was successful. "Everyone" seems focused on finding the "biggest ones"- which are rare and therefore not too relevant. E.g. They are building/have built huge arrays that detect for events that occur once a century in a 1 sq km.
I started here:
http://www.fourmilab.ch/documents/ohmygodpart.html
And did some seaches. There is no doubt that this concerns the cutting edge of research and we are barely beginning to get some answers- nature is providing "for free" a superduper Superconducting Super Collider- and of course, the question of what "exactly" is making these particles go so fast. This is all very fun, but wish they would provide more practical answers:)