According to Asymco Apple once saw "quantum jump" in retail store traffic, but only in the actual meaning of the term in question-- as in less of a "giant leap" and more of a "specific, discrete jump."
How so? Fiscal 2012 saw 372 million visits to Apple Stores. Fiscal 2013 saw 395 million. The numbers might be massive (the increase comes to 23m, the approximate population of Australia), but as plotted graphically (above) against past visitor number, growth appears to be relatively modest, if not on the slowdown.