INVENTORIES

Inventories are stated at the lower of cost, determined by the last-in, first-out (LIFO) method, or market.

Inventories consist of the following:



In Thousands	March 31, 2018			December 31, 2017

Raw materials	$	25,257		$	32,928
Work-in-process	19,681			22,753
Finished goods	103,380			88,497
Total Inventory at FIFO cost	148,318			144,178
Adjust to LIFO cost	(53,820		)	(51,813		)
Inventory, net	$	94,498		$	92,365

LIFO pools are established at the end of each fiscal year. During the first three quarters of every year, LIFO calculations are based on the inventory levels and costs at that time. Accordingly, interim LIFO balances will fluctuate depending on those inventory levels and costs.

In the first quarter of 2018, LIFO adjustments were recorded, increasing cost of sales by $2.0 million, versus LIFO adjustments increasing cost of sales by $4.4 million in the first quarter of 2017. During the first quarter of 2018, the Company liquidated a portion of the LIFO inventory layer in the aluminum wire pool established in prior years. This liquidation had an insignificant effect on the net income of the Company. During the first quarter of 2017, the Company did not liquidate any LIFO inventory layers established in prior years.