I think changes to phrases that don't change their meaning are interesting. Example: an ice cold beer and a nice cold beer mean pretty much the same thing.
I heard another one this morning on the radio in a story about coal. The phrase used is fluctuates widely, but I know I've also heard fluctuates wildly. Looking at the ngram, I'm surprised to see that widely is far more popular (although with 0 smoothing, it does fluctuate wildly.
Where did either of these phrases come from? Which came first and which is more correct? Wildly makes more sense to me in most contexts, but widely makes sense too.