AFAIK, the sugars in some type of pears consists of up to 80% fructose. But I also don't know of a natural source of pure fructose.
That is a high percentage of fructose in pears. It makes me wonder if that is what makes pears a cough remedy, as practiced by Chinese:
Steamed Pear with Rock Sugar - home remedy for cough & sore throat - SoluHeal