We have a (Java) pixel-camera app on Android that does its transform calculations using C++ due to an obvious speed advantage over doing them in Java. These figures could be taking such hybrid apps into account (or not).

[creator of the slide deck] As empressplay mentioned, there could be specific needs that warrants that. Those numbers are from a Vision Mobile survey and its replies: http://www.developereconomics.com/reports/developer-economic...

Do you have a video/talk with the slides? because it feels a bit like a movie without the sound when one only sees the slides.

Unfortunately not, it wasn't filmed. And I agree, slide decks need the presentation to go with them. With numbers, there's a lot up to you to draw conclusions.