There is one prison complex located in Nicosia, the capital city. The average daily prison population over the past few years has increased from a low of 180 to a high of 230. The Republic of Cyprus is a member of the Council of Europe, and as such has agreed to implement the European Prison Rules for the treatment of prisoners adopted by the Council of Europe on February 12, 1987. Since 1991 the Cyprus Prisons Department has incarcerated prisoners from 56 different countries, many of them in the surrounding region. The prison staff is primarily concerned with the safe detention of inmates under conditions that guarantee human dignity. Thus, discrimination based on race, color, sex, language, religion, politics, national origin, birth, economic status, etc., is prohibited. Staff encourage inmate self-esteem by offering opportunities for education, vocational training, recreation, problem-solving, and self-evaluation. In the closed prison, a wall defines the outer perimeter, which is monitored with cameras and electronic security. Inmates placed in the closed prison must serve approximately one-third of the sentence in the closed prison before being transferred to the open prison or work release center. An inmate may file a complaint with the Prison Board if not satisfied with the prison administration's response to a complaint. The Board has the authority to overrule in whole or in part any punishment imposed by the prison director.