The Ministry of Finance published the General Communiqué on Tax Procedure Law number 457 (the “Communiqué”) in Official Gazette number 29528 on 10 November 2015. The Communiqué determines the revaluation rate for 2015 as 5.58% and this rate will also apply to the last provisional taxation period of 2015. The revaluation rate is used to update various taxes, administrative penalties and other monetary amounts on an annual basis.
Article 298(B) (duplicated) of the Tax Procedure Law number 213, defines the revaluation rate as the increase rate for the Domestic Producer Price Index.
The Turkish Statistical Institute announces the rate during October each year (including October), as a comparison with the same period in the previous year. The Ministry announces the rate in the Official Gazette.
Please see this link for the full text of the Communiqué (only available in Turkish).