ExxonMobil Corporation had net income of $41.0 billion in 2011. Inventories under the LIFO method used by the company were $11.7 billion in 2011. Inventory would have been $25.6 billion higher if the company had used FIFO. Why do you suppose ExxonMobil’s management chooses to use the LIFO inventory method? On what economic conditions, if any, do those reasons depend?