A reconciliation of income tax expense, computed by applying the federal statutory rate to pre-tax income to our effective income tax expense is as follows:



	2013		2012		2011
	(In thousands)
Income tax expense computed by applying the statutory rate	$	105,514	$	13,791	$	111,651
State income tax, net of federal benefit	8,290		1,084		8,941
Statutory depletion and other	2,919		1,351		2,543
Income tax expense	$	116,723	$	16,226	$	123,135

For the periods indicated, the total provision for income taxes consisted of the following:



	2013		2012			2011
	(In thousands)
Current taxes:
Federal	$	15,845	$	2,084		$	(3,159	)
State	146		(1,388		)	743
	15,991		696			(2,416		)
Deferred taxes:
Federal	87,839		13,768			109,363
State	12,893		1,762			16,188
	100,732		15,530			125,551
Total provision	$	116,723	$	16,226		$	123,135

Deferred tax assets and liabilities are comprised of the following at December 31:



	2013			2012
	(In thousands)
Deferred tax assets:
Allowance for losses and nondeductible accruals	$	77,285		$	74,890
Net operating loss carryforward	61,055			56,020
Alternative minimum tax credit carryforward	17,258			1,972
	155,598			132,882
Deferred tax liability:
Depreciation, depletion, amortization and impairment	(943,411		)	(819,893		)
Net deferred tax liability	(787,813		)	(687,011		)
Current deferred tax asset	13,585			8,765
Non-current—deferred tax liability	$	(801,398	)	$	(695,776	)

Realization of the deferred tax assets are dependent on generating sufficient future taxable income. Although realization is not assured, management believes it is more likely than not that the deferred tax asset will be realized. The amount of the deferred tax asset considered realizable, however, could be reduced in the near-term if estimates of future taxable income are reduced. At December 31, 2013, we have federal net operating loss carryforwards of approximately $146.5 million which expire from 2015 to 2033.