Income Taxes

The effective tax rates for the three-month periods ended March 31, 2017 and 2016 are as follows:



	Three Months Ended
	March 31,		March 31,
	2017		2016
Effective tax rate	30.6	%	34.3	%

Our effective income tax rate was 30.6% and 34.3% in the first quarter of 2017 and 2016, respectively. The tax rate in the first quarter 2017 was lower than the U.S. statutory tax rate due primarily to tax benefits recorded upon vesting of restricted stock units and favorable tax rates on foreign earnings, offset by the impact of state taxes, tax expense for withholding taxes on the anticipated distribution of earnings in China, and other various permanent items.

Our continuing practice is to recognize interest and/or penalties related to income tax matters as income tax expense. For the three months ended March 31, 2017, and March 31, 2016, we recorded $176 and $184, respectively, of interest or penalties in income tax expense.