INCOME TAXES	6 Months Ended
Jun. 30, 2015
INCOME TAXES
INCOME TAXES	13. INCOME TAXES Our effective income tax rates for the three and six months ended June 30, 2015 were 4.9 percent and 20.3 percent, respectively, compared to our effective income tax rates of 27.9 percent and 15.3 percent, respectively, for the three and six months ended June 30, 2014. The effective income tax rates were determined using the estimated annual effective tax rate after considering discrete income tax items for each respective period. The effective income tax rates for the three and six months ended June 30, 2015 were lower than the United States statutory federal income tax rate primarily due to various favorable permanent differences including deductions for depletion and manufacturing activities. The effective income tax rates for the three and six months ended June 30, 2014 were lower than the United States statutory federal income tax rate primarily due to various permanent differences including deductions for manufacturing activities and the cumulative $3.5 million favorable impact of changes in uncertain tax positions.

INCOME TAXES

6 Months Ended

Jun. 30, 2015

13. INCOME TAXES

Our effective income tax rates for the three and six months ended June 30, 2015 were 4.9 percent and 20.3 percent, respectively, compared to our effective income tax rates of 27.9 percent and 15.3 percent, respectively, for the three and six months ended June 30, 2014. The effective income tax rates were determined using the estimated annual effective tax rate after considering discrete income tax items for each respective period. The effective income tax rates for the three and six months ended June 30, 2015 were lower than the United States statutory federal income tax rate primarily due to various favorable permanent differences including deductions for depletion and manufacturing activities. The effective income tax rates for the three and six months ended June 30, 2014 were lower than the United States statutory federal income tax rate primarily due to various permanent differences including deductions for manufacturing activities and the cumulative $3.5 million favorable impact of changes in uncertain tax positions.