Chances of receiving epic and unique?

In my observations on Tespia it was about 95% rare, 4.8% epic, 0.2% unique on reveal.

In terms of cubing it's similar ~5% chance to go rare->epic, and I've heard claimed the same ~5% chance to go epic->unique, which would make the chance of both at once 0.25% (matches up with Tespia observations, for a total of 95% rare, 4.75% epic, 0.25% unique).

That is really low... :| Thanks for your reply.