Dixons sold 5 tablets a second in the week before Christmas

"Dixons Retail had a bumper Christmas thanks to 'phenomenal' sales of tablet computers - with five a second flying off its shelves in the week before Christmas.
Heavy demand for the gadgets helped the owner of PC World and Currys overcome competition from clearance sales at Comet, which went into administration towards the end of last year.
Apple iPads made up a third of tablet sales, but Dixons also saw strong demand for the Samsung Galaxy and Google Nexus models.
Dixons sold more than a million tablets in the UK and Ireland in the three months to January 5, pushing its overall like-for-like sales up by a better-than-expected 8 per cent in the period."

Source:  Daily Mail, 17th January 2013

Note - This implies that they were all sales in store, but it probably includes online sales too