12. Inventory

The majority of our inventory is accounted for under the retail inventory accounting method (RIM) using the last-in, first-out (LIFO) method. Inventory is stated at the lower of LIFO cost or market. The cost of our inventory includes the amount we pay to our suppliers to acquire inventory, freight costs incurred in connection with the delivery of product to our distribution centers and stores, and import costs, reduced by vendor income and cash discounts. The majority of our distribution center operating costs, including compensation and benefits, are expensed in the period incurred. Inventory is also reduced for estimated losses related to shrink and markdowns. The LIFO provision is calculated based on inventory levels, markup rates and internally measured retail price indices.

Under RIM, inventory cost and the resulting gross margins are calculated by applying a cost-to-retail ratio to the inventory retail value. RIM is an averaging method that has been widely used in the retail industry due to its practicality. The use of RIM will result in inventory being valued at the lower of cost or market because permanent markdowns are currently taken as a reduction of the retail value of inventory.

We routinely enter into arrangements with vendors whereby we do not purchase or pay for merchandise until the merchandise is ultimately sold to a guest. Activity under this program is included in sales and cost of sales in the Consolidated Statements of Operations, but the merchandise received under the program is not included in inventory in our Consolidated Statements of Financial Position because of the virtually simultaneous purchase and sale of this inventory. Sales made under these arrangements totaled $1,800 million, $1,736 million and $1,581 million in 2012, 2011 and 2010, respectively.