The Equalization of Land Rights Act Article 39

The original assessed value of land or the current transaction land value declared at the time of its last transfer as referred to in the preceding Article shall be duly adjusted with the price index announced by the government, and the total amount of the increased value of land shall then be computed on the basis of the adjusted figures.
中文原文 平均地權條例第39條
前條原規定地價或前次移轉時申報之現值,應按政府公告之物價指數調整後,再計算其土地漲價總數額。

English translation for reference only; the Chinese text prevails. Not legal advice.