Searching the term "pinky finger" in
google news archive seems to indicate it having very little usage until the 1980's since when it's rise has been exponential. However it does crop up early in one or two 1940's American newspapers. I have no doubt it is an imported Americanism in it's current popular form. I cannot imagine my own grown-up children (from England) saying anything other than "little finger", for instance.
Is pinkie popularly used in Scotland? Perhaps the Americans got it from the Canadians, who got it from Scotland originally.
