The effective tax rates for the three and six months ended June 29, 2019 were 23.6% and 24.2%, respectively. The effective tax rates for the three and six months ended June 30, 2018 were 21.9% and 6.2%, respectively. For the six months ended June 29, 2019, the primary difference between the U.S. federal statutory tax rate and the Company’s consolidated effective tax rate was due to $1,798 of tax expense related to global intangible low-taxed income (“GILTI”) and $1,766 of higher state income tax expenses versus the prior year period. The effective tax rate was partially offset by a $1,375 tax benefit related to the reversal of tax reserves no longer needed, a $1,284 tax benefit related to foreign-derived intangible income (“FDII”) and a $746 tax benefit related to the cessation of certain publishing operations. For the six months ended June 30, 2018, the primary difference between the U.S. federal statutory tax rate and the Company’s consolidated effective tax rate was due to the $22,155 tax benefit related to tax windfalls from stock compensation and a $1,859 tax benefit related to the cessation of operations of the Company’s Mexican subsidiary.

The differences between the U.S. federal statutory tax rate and the Company’s consolidated effective tax rate were as follows:

	Three Months Ended						Six Months Ended
	June 29,			June 30,			June 29,			June 30,
	2019			2018			2019			2018
U.S. federal statutory tax rate		21.0	%		21.0	%		21.0	%		21.0	%
State income taxes (net of federal benefit)		0.4	%		2.2	%		3.1	%		2.3	%
Reserves for uncertain tax positions		(2.0	%)		0.3	%		(2.4	%)		0.2	%
Cessation of operations		(1.1	%)		0.0	%		(1.3	%)		(1.6	%)
Research and development credit		(0.4	%)		(0.1	%)		(1.1	%)		(0.4	%)
Tax windfall on share-based awards		0.1	%		(4.5	%)		0.2	%		(18.9	%)
GILTI		1.3	%		2.9	%		3.2	%		4.5	%
FDII		(0.9	%)		(1.2	%)		(2.3	%)		(1.9	%)
Impact of foreign operations		2.2	%		0.6	%		1.8	%		(0.4	%)
Other		2.8	%		0.7	%		2.0	%		1.4	%
Total effective tax rate		23.6	%		21.9	%		24.2	%		6.2	%