Income Taxes

The following table provides details of income taxes (in millions, except percentages):



	Three Months Ended March 31,
	2019			2018
Income before income taxes	$	44.5		$	41.4
Income tax provision	$	13.4		$	7.0
Effective tax rate	30.1		%	16.9		%

The Company's effective tax rate during the three months ended March 31, 2019 differs from the federal statutory rate of 21%, primarily due to the benefit of the federal research and development ("R&D") credit and foreign earnings taxed at lower rates partially offset in the U.S. by the Base Erosion and Anti-Abuse Tax and state income taxes. The increase in the rate reflects the inability to fully benefit the discrete charges in the period and the net impact of unrecognized tax benefits.

The effective tax rate during the three months ended March 31, 2018 differs from the federal statutory rate of 21% primarily due to the net impact of previously unrecognized tax benefits.

As of March 31, 2019, the total amount of gross unrecognized tax benefits was $181.6 million, of which $178.2 million, if recognized, would affect the effective tax rate.

The Company engages in continuous discussions and negotiations with tax authorities regarding tax matters in various jurisdictions. It is reasonably possible that the balance of unrecognized tax benefits could decrease up to $30.4 million within the next twelve months due to lapses of applicable statutes of limitations and the completion of tax review cycles in various tax jurisdictions.