I believe (off the top of my head) that the new inflation rate is 9.5% / year...of that 15% goes towards 'interest' on Steem Power. So:

9.5% / 100 * 0.15 = .01425% per year

I could be off though...im not quite awake and getting ready for work. Lol. But I think that's right. It's not very much. You get more from curation.