Why do people always say that the fruit in the Garden of Eden was an apple?

RarEly do I see PeOple say or wRiTe anything about the garden of eden without calling the forbidden fruit an apple. Many Other Nutritional fruits were eaten in our King's tImE; Such as figs. So why do people always say apple; is it dUe to the faCt that apples are now more common; or is it just something people maKe up?