Any official stats on authorship impact on SERP click-throughs?

[BostonWright]

I'm trying to make another push to get authors on my site to set up authorship. Can anyone point me in the direction of any official stats from Google on the impact of authorship on SERP click-throughs? I've seen some articles on SEO sites that make it seem like the lift is anywhere from 20-40%, but those seem to be site specific cases. I'm wondering if there's any broader studies out there or official data from G.

Thanks!

[EGOL]

SEO sites that make it seem like the lift is anywhere from 20-40%

I don't think that it did anything for my CTR.

I don't think that it did anything for my rankings either.