Administrative Regulations for Number Portability Services of Telecommunications Enterprises Article 21

Before the end of January and the end of July each year, each Operator shall compile and submit information such as the number of Subscribers ported to/from its networks, the failure rate of porting process, average duration of porting process, and so on, for the previous six months to the competent authority. The report formats shall be announced by the competent authority.
中文原文 電信事業號碼可攜服務管理辦法第21條
經營者應於每年一月底及七月底前提供彙整其前六個月攜碼用戶移入與移出數量、移轉作業失敗率、平均移轉作業時間等資料,提報予主管機關;其提報格式,由主管機關公告之。

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