This looks to me like a misunderstanding of Müller & Bostrom 2014. The actual figure is that 50% of AI researchers give a 10% probability of HLMI by 2022.
Müller, V. C., & Bostrom, N. Future progress in artificial intelligence: A survey of expert opinion. In V. C. Müller (Ed.), Fundamental Issues of Artificial Intelligence. Berlin: Springer. 2014
That's what I thought at first, too, but then I looked at the paper, and their figure looks right to me. Could you check my reasoning here?
On p.11 of Vincent's and Nick's survey, there's a graph "Proportion of experts with 10%/50%/90% confidence of HLMI by that date". At around the the 1 in 10 mark of proportion of experts -- the horizontal line from 0.1 -- the graph shows that 1 in 10 experts thought there was a 50% chance of HLAI by 2020 or so (the square-boxes-line), and 1 in 10 thought there was a 90% chance of HLAI by 2030 or so (the triangl...
A summary and review of Bostrom's Superintelligence is in the December issue of Reason magazine, and is now posted online at Reason.com.