The administrative system, which was established by Zhabdrung Ngawang Namgyal in the 17th century, underwent modifications during the 20th century and the position of penlop was abolished. Instead a Dzongda (instead of Dzongpon) was appointed in the twenty dzongkhags (districts), who were responsible to the home ministry. The Dzongrab aids the Dzongda in his duties. The most populated districts have been divided into sub-districts, dungkhag, which are led by a Dungpa. Each district is divided into blocks (gewogs), administrative units comprising several villages. Here decisions are passed by a village headman, elected by the villagers of the block, called gup. An administrative officer assists the gup.