I don't know the true answer to your question, but since encoding is expected to reach just 5X of VP9 by the end of this year, I think decoding is in the same order.
The plan, of course, is in the coming years there will be decoders baked into the silicon so the computational complexity is offloaded from the CPU and therefore becomes (in some ways) irrelevant.
The plan, of course, is in the coming years there will be decoders baked into the silicon so the computational complexity is offloaded from the CPU and therefore becomes (in some ways) irrelevant.