it is not immediately clear to me that that stat is on the up
Not sure what that means. Does it mean that you’re not sure the number is rising? Or does it mean that you’re not sure the stat is accurate?
English is definitely the global language. Travel, business, global infrastructure, science, diplomacy, all communicate primarily in English. But English is far from “universal.”
A truly universal language is an impossibility. Just look at English. With just about 10% who speak it, and another 10% who have some degree of familiarity with it, it is already fractured into dialects that can be almost incomprehensible to one another. I find Indian English difficult to understand, and Singaporean English all but impossible to comprehend. (Of course, those speakers can usually code switch into a more standard register.) Any universal language would swiftly break apart as well.
Plus, I don’t know what the advantages of a universal language actually are. We get most of supposed benefits from English’s global status. What’s left are vague claims that such a language would bring world peace and other such benefits. Nice, but unlikely.