During 2010, Phelps Corporation reported net sales of $4,000,000, net income of $2,200,000, and depreciation expense of $80,000. Phelps also reported beginning total assets of $1,000,000, ending total assets of $1,500,000, plant assets of $800,000, and accumulated depreciation of $500,000. Phelps's asset turnover ratio is ??