Last year, Welk Company had 16,000 units in its beginning inventory (FIFO inventory method). During the year, Welk’s variable production costs were $6 per unit and its fixed manufacturing overhead costs were $4 per unit. Welk’s operating income for the year was $24,000 higher under absorption costing than it was under direct (variable) costing. Given these facts, what was the number of units in the ending inventory?