I've been buying bags of grapefruits from Costco for many years. They are sold by the bag not by the pound or piece. This year, because of the thick pith, they are very large so you only get six or seven per bag. In past years there were several more in the bag. and it's not like there is more flesh in these grapefruit, just more peel/pith. Is this related to the specie or growing conditions?