The following table shows selected data for Wong Corporation for the past five years ended December 31, 2014:

2018 2017 2016 2015 2014

Net sales $19,500 $17,400 $18,200 $16,500 $14,900

Cost of goods sold 9,500 10,300 9,500 8,900 8,000

Inventory 13,000 12,200 8,700 9,500 9,300

Net accounts receivable 7,500 6,800 7,200 7,000 6,500

Prepare an analysis showing the trend percentages for the four years 2015-2018, using 2015 as the base year.