I might show the GapMinder 8th grade math achievement data to my students at the beginning of the semester in Physics.
I would do this to let them know that the US is not as bad at math as the media might have you believe, and also to show them how cool GapMinder is. Perhaps this would help with their confidence in math.
"Unveiling the beauty of statistics for a fact based world view"
Looking at GapMinder, you can compare so many things, and see so many correlations. A history or social science class could come back to this data over and over during the semester. As a Physics teacher, I don't think that I would use GapMinder often. But I would present it as an attractive way to present data.