On January 1, 2014, a company has assets of $15.10 billion and stockholders' equity of $8.90 billion

On January 1, 2014, a company has assets of $15.10 billion and stockholders' equity of $8.90 billion. On January 1, 2015, the same company has assets of $19.10 billion and stockholders' equity of $9.90 billion. During 2014, the company had total sales revenue of $9.90 billion and total expenses of $6.10 billion. If the company doesn't have other sources of revenue, its net profit margin during 2014 is closest to: