DOC purchased property for R320,000 exactly 10 years ago. The land included in the price was valued at R120,000. The property was estimated to have a useful economic life of 20 years. DOC has now had the property revalued (for the first time) by a professional valuer. The total value had increased to R800,000, the land now being valued at R200,000. The useful economic life remained unchanged. Calculate the amount that should be credited to DOC’s revaluation reserve.