Purple Company acquires an office building at a cost of $1,000 on January 1, 2021. The building expects to have a 30-year useful life with residual value of $100 at the end of the estimated useful life. The asset is accounted for under the revaluation model (proportional method) and revaluations are carried out every year. The company uses the straight-line method to record depreciation and both the useful life and residual value remain unchanged throughout revaluation. Also assume that the company always adjusts for depreciation expense difference under the revaluation model and the cost model. The fair value of the office building is appraised at $1,100, $900 and $1,000 on December 31, 2021, 2022 and 2023, respectively.

Determine the amount for Changes in Revaluation Surplus to be reported on the Statement of Comprehensive Income on December 31, 2021. Round your answer to the nearest dollar if necessary. (Hint: if it is other comprehensive loss, please use a negative sign for your answer) (7 marks)