Nathans Grills, Inc., imports and sells premium-quality gas grills. The company had the following layers in its LIFO inventory at January 1, 2014, at which time the replacement cost of the inventory was $900 per unit.

Year LIFO Layer Added Units Unit Cost

2011 100 $600

2012 50 700

2013 30 800

The replacement cost of grills remained constant throughout 2014. Nathans sold 200 units during 2014. The company established the selling price of each unit by doubling its replacement cost at the time of sale.

Calculate gross margin percentage assuming 1) purchases of 220 in 2014 and 2) purchases of 110 in 2014. Nathans uses a periodic inventory system.