Analysis of information sources in references of the Wikipedia article "Κατάλογος των πιο επιτυχημένων singles" in Greek language version.
More than 4 million copies of the single were sold in the US alone, and more than 10 million were sold around the globe.
...while Autry's version of "Rudolph the Red-Nosed Reindeer" sold more than 12.5 million copies
