(1) Primarily consists of computers, mobile phones and tablets.(2) Primarily consists of audio, fitness equipment, furniture and accessories, mattresses and personal electronics. The decrease in comparable store sales for the three month period ended September 30, 2012 was driven primarily by a decrease in net sales in the video and other categories, partially offset by increases in net sales in the appliance and computing and mobile phones categories. The video category comparable store sales decline was driven by a double digit decrease in unit demand partially offset by a single digit increase in average selling prices. The decrease in comparable store sales for the other category was primarily a result of double digit comparable store sales decreases in cameras, camcorders and small electronics, partially offset by growth in the mattress category. The appliance category increase in comparable store sales was driven by an increase in average selling price due to favorable mix shifts. The computing and mobile phones category was led by increased demand in the offering of tablet computers and mobile phones, partially offset by declines in notebook and netbook computers. Gross profit margin, expressed as gross profit as a percentage of net sales, increased 107 basis points for the three months ended September 30, 2012 to 29.6% from 28.6% for the comparable prior year period. The increase was largely due to an increase in gross profit margin rates in the video and appliance categories, partially offset by modest declines in the computing and mobile phone and other categories. The increase in the video gross margin rate was largely due to a favorable mix of larger screen size LED models, which carry higher gross margin rates than smaller screen LCD models. The appliance category was favorably impacted by a continued mix shift to higher efficiency products which generate higher gross margin rates.