The latest tariff stipulations were issued in 2005 and 2007 and take into account environmental considerations, the level of technology development, and the inflation rate.
Ang pinakabagong taripa takda ay ipinalabas noong 2005 at 2007 at isinasaalang-alang account ng kapaligiran, ang antas ng pag-unlad ng teknolohiya, at sa implasyon rate.