Our bad. Should have put some p-values in the text itself. All those differences are statistically significant, typically at <0.001 levels.

All the statistical output, including confidence intervals, is available via clicking through the links to the dataset itself, available here: https://www.statwing.com/open/datasets/88ed02bd6dda2f813ba98...

Edit: We added a couple notes about this in the blog post, thanks for the feedback.