On January 1, 2011, a company has assets of $15.50 billion and stockholders' equity of $8.50 billion. On January 1, 2012, the same company has assets of $19.50 billion and stockholders' equity of $9.50 billion. During 2011, the company had total sales revenue of $9.50 billion and total expenses of $6.50 billion. The company's asset turnover ratio for 2011 is: 2.44 0.54 0.49 0.15