Occupancy related expenses include: (1) building rent and depreciation, (2) building utility costs, (3) equipment related to our stores and distribution locations, and (4) FAST Solutions SM (industrial vending) equipment (we consider the vending equipment to be a logical extension of our store operation and classify the expense as occupancy). The increase in 2012 was driven by (1) a dramatic increase in the amount of FAST Solutions SM (industrial vending) equipment as discussed earlier in this document, (2) an increase in the number of locations, and (3) increased investment in our distribution infrastructure over the last several years. Almost all of our occupancy increase in 2012 related to item (4) a dramatic increase in the amount of FAST Solutions SM (industrial vending) equipment, as our energy savings offset most of the increase relating to items (1) and (3). The energy savings were driven by our efforts to lower energy consumption, a mild winter, and a drop in natural gas prices during the heating season. The increase in 2011 was driven by the same factors noted above with one exception; in 2011 approximately 50% of the increase was due to rising utility costs.
Our selling transportation costs consist primarily of our store fleet as most of the distribution fleet costs are included in the cost of sales. Selling transportation costs included in operating and administrative expenses increased in 2012; however, they increased at a rate less than sales growth. The increase in 2012 was primarily due to elevated fuel prices in the first quarter, and, in the case of the first, second, and third quarters, the impact of the 2011 expansion of our fleet related to additions to our non-store sales personnel, particularly our industrial vending vehicles. The increase in 2011 was primarily related to the increase in per gallon fuel costs discussed below and the expansion of our fleet related to additions to our non-store sales personnel, particularly our industrial vending vehicles. Our selling and transportation costs in the fourth quarter of 2012 were comparable to those in the fourth quarter of 2011 because the per gallon fuel costs only grew nominally and the number of our industrial vending vehicles had normalized. Conversely, the increase in the fourth quarter of 2011 from the fourth quarter of 2010 was driven by the dramatic increase in per gallon fuel costs and the ramp up in the number of our industrial vending vehicles.