Left-handedness is the preference for the left hand over the right for everyday activities such as writing. Most left-handed people favor their right hand for some activities, and many exhibit some degree of ambidexterity. Left-handedness is relatively uncommon; 90 to 93 percent of the adult population is right-handed. In baseball, left-handed pitchers tend to fare better against left-handed batters, and most teams keep at least on lef-handed reliever in the bullpen in case they are needed.