The "Outdoor Service" was divided into geographical areas called Collections, each overseen by a Collector (a senior official who acted as the Board's representative). Initially there were ninety-two Collections (formed by merging the previously separate Customs Collections and Excise Collections) but these were later reduced: to thirty-nine by 1930, twenty-nine by 1971. The Collections were subdivided into Districts (each overseen by a Surveyor) within which were several Stations, each staffed by one or more Officers of Customs and Excise. In each Collection, the Stations were responsible for assessment of duty while the Collector's Office focused on collection of revenue.