On the StackOverflow blog there's an interesting post that looks at the differences in programming languages between countries based on their current state, either a developing country or a wealthy one (or somewhere in between).
Here at Stack Overflow, we’re interested in using our data to share insights about the worldwide software development community. [...] This leads us to wonder how else programming technologies may differ between rich and poor countries, and how that affects our picture of the global software development industry. In this post, we’ll explore these differences, and show that’s it’s useful to segment the software development industry into high-income countries and the rest of the world.
All the analyses explored here were performed on 2017 so far (January-August), on the 250 tags that had the most traffic during that time.
They investigated some of the major programming languages and platforms (including PHP) and found some interesting negative and positive correlation results. The post then covers how they split the list of countries in two (wealthy vs developing) and show results of the technologies they use. They include graphs for each of the points they make and link over to their StackOverflow Insights site where you can gather statistics for evaluation of your own.