Someone had posted this information in, I think, the Beta forums, but I cant find it now. There was a table with the relative rarity of all the runes - i.e. something like:
-Tal: 1 in 8
-Vex: 1 in 500
-Zod: 1 in 4500
Or something like that. Anyone still have that info or a link to that post or anything?