The Council is a unicameral body consisting of 51 Council members, whose districts are defined by geographic population boundaries that each contain approximately 157,000 people. Council members are elected every four years, except that after every census held in years divisible by twenty, districts are redrawn, requiring two consecutive two-year terms, the second of which is held in the redrawn districts. The Speaker of the Council, selected by the 51 Council members, is often considered the second most powerful post in New York City's government after the Mayor.