By Katie Marsal

Published: 10:00 AM EST (07:00 AM PST)

Apple's retail store revenue increased 72.8 percent year over year to $2.58 billion in the June quarter, an increase attributed to consumer demand for the iPad. The company's retail expansion will continue this Saturday with the opening of its largest U.K. store in Covent Garden.

While visitors per store increased 38.7 percent in the three-month frame ending in June, and same-store Mac sales grew 21.8 percent, the real star of the show was the iPad, which helped non-Mac revenues grow 106.3 percent year over year. Analyst Charlie Wolf with Needham & Company on Wednesday issued a note to investors in which he detailed the role the iPad played in Apple's retail success last quarter.

"To place the ($2.58 billion) number in perspective, Apple Store revenues in June were greater than Apple's total quarterly revenues from the second quarter of fiscal 1996 through the fourth quarter of fiscal 2004," Wolf wrote.

Wolf has long referred to Apple's retail stores as the "fourth leg of the stool" in Apple's business model. That changed, he said in his latest note, with the iPad, which has joined the iPod, iPhone and Mac as a crucial element of the company's business. Still, he said, Apple's stores continue to represent a strong component of Apple, regardless of being overtaken by the iPad.

In all, Apple's stores accounted for 16.4 percent of the company's worldwide revenues in June, up slightly from the 15.3 percent they represented a year ago. Retail revenues have been on a decline since the second quarter of 2008, as iPhone sales through other channels, such as worldwide carrier partners, make up a larger portion of the company's sales.

First shots of Covent Garden London store

The latest retail store from Apple is set to open this Saturday, but electricpig.co.uk sent along pictures of the new store at Covent Garden in London. The two-story location stays true to the original architecture of the building, and the store will be the largest in the U.K.