KNO Enterprises develops a patent on January 1, 2015, and the costs involved with patent approval are $8,400. The legal life of the patent is 20 years, but KNO projects that it will provide useful benefits for only 12 years. At January 1, 2018, the company discovers that a competitor will introduce a new product, making this patent useless in five years. How much amortization should be recorded in 2015, 2016, and 2017?