Blue Corp. constructed a machine at a total cost of $70 million. Construction was completed at the end of 2017, and the machine was placed in service at the beginning of 2018. The machine was being depreciated over a 10-year life using the straight-line method. The residual value is expected to be $4 million. At the beginning of 2021, Blue decided to change to the sum-of-the-years'-digits method. Ignoring income taxes, what will be Blue's depreciation expense for 2021