Evan Engineering Group receives royalties on a technical manual written by two of its engineers and sold to a publishing company

Evan Engineering Group receives royalties on a technical manual written by two of its engineers and sold to a publishing company. Royalties are 10% of net sales, receivable on October 1 for sales in January through June and on April 1 for sales in July through December of the prior year. Sales of the manual began in July 2015, and Evan accrued royalty revenue on $33,180 of sales at December 31, 2015. Evan received royalties of $2,698 on April 1, 2016. On October 1, 2016 Evan received royalties of $3,025. The 2nd half of 2016 sales were estimated to be $41,880 What is Evan's 2016 royalty revenue?