(in thousands)	2020			2019			2018
Current:
Federal	$	33,698		$	19,090		$	33,362
State		4,276			2,091			2,618
Foreign		491			(194	)		1,611
		38,465			20,987			37,591
Deferred:
Federal		(8,475	)		2,084			1,398
State		(893	)		(280	)		186
Foreign		(231	)		(746	)		(1,642	)
		(9,599	)		1,058			(58	)
Total	$	28,866		$	22,045		$	37,533

The following is a reconciliation of income taxes at the statutory tax rate to the Company's effective tax rate:

	2020			2019			2018
Federal taxes at statutory rate		21.0	%		21.0	%		21.0	%
State taxes, net of federal tax benefit		2.0			1.3			1.3
Research and development tax credit		(0.6	)		(0.5	)		(0.4	)
Federal permanent items		(0.2	)		(0.3	)		(0.1	)
Effect of foreign operations		0.1			(1.1	)		(0.2	)
Other		(1.0	)		0.4			0.3
Effective tax rate		21.3	%		20.8	%		21.9	%

At December 26, 2020, we had $1.1 million of unrecognized tax benefits, all of which would affect our effective tax rate if recognized.

The following table summarizes the change in unrecognized tax benefits for the three years ended December 26, 2020:

(in thousands)	2020			2019			2018
Balance at beginning of year	$	2,301		$	2,390		$	2,301
Reductions due to lapses in statutes of limitations		—			(200	)		(95	)
Reductions due to tax positions settled		(1,308	)		—			(368	)
Reductions due to reversals of prior year positions		(202	)		(28	)		(4	)
Additions based on tax positions taken during the current period		269			139			556
Balance at end of year	$	1,060		$	2,301		$	2,390

We recognize interest and penalties related to unrecognized tax benefits in income tax expense. As of December 26, 2020, accrued interest and penalties related to unrecognized tax benefits were immaterial.

Deferred income taxes result from timing differences in the recognition of revenue and expense between tax and financial statement purposes. The sources of temporary differences are as follows:

(in thousands)	December 26, 2020			December 28, 2019
Assets:
Inventories	$	11,346		$	9,545
Accounts receivable		16,452			10,695
Operating lease liability		9,352			7,273
Accrued expenses		3,550			1,974
Foreign tax credits		631			844
Total deferred tax assets		41,331			30,331
Valuation allowance		(1,256	)		(844	)
Net deferred tax assets		40,075			29,487
Liabilities:
Depreciation		10,586			10,296
Goodwill and intangible assets		12,419			11,742
Operating lease right of use asset		8,560			6,656
Other		(121	)		416
Gross deferred tax liabilities		31,444			29,110
Net deferred tax assets	$	8,631		$	377

Based on our history of taxable income and our projection of future earnings, we believe that it is more likely than not that sufficient taxable income will be generated in the foreseeable future to realize the remaining net deferred tax assets.

We file income tax returns in the United States, Canada, China, India, and Mexico. All years before 2017 are closed for U.S. federal tax purposes. Tax years before 2016 are closed for the states in which we file. Tax years before 2017 are closed for tax purposes in Canada. Tax years before 2017 are closed for tax purposes in China. Tax years before 2015 are closed for tax purposes in Mexico. All tax years remain open for India.

The Coronavirus Aid, Relief, and Economic Security (CARES) Act was signed into law on March 27, 2020 in response to the COVID-19 pandemic. The CARES Act, among other things, allows net operating losses incurred in 2018, 2019, and 2020 to be carried back to each of the five preceding taxable years to generate a refund of previously paid income taxes. The CARES Act also includes provisions relating to increased interest expense deductibility, refundable payroll tax credits, deferment of employer social security payments, and technical corrections to tax depreciation methods for qualified improvement property. Most significant to the Company is the accelerated depreciation on qualified improvement property. The Company continues to monitor Coronavirus-related Federal and state relief opportunities.