Not every category is worth examining at every organization. Part of the first conversation is telling you which ones are not — a category already well managed, recently tendered, or bound by an agreement with real term remaining is one we would say so about.
These figures describe ranges observed across an industry, drawn from samples that may or may not resemble your organization. We publish the source and the sample size for each one because a range is useful for orientation even when it cannot be a conclusion. None of them describe you.