India; and a private bank Bandhan Bank. Reserve Bank of India has its eastern zonal office in Kolkata, and India Government Mint, Kolkata is one of the four mints in India. Some of the oldest public sector companies are headquartered in the city such as the Coal India Limited, National Insurance Company, Garden Reach Shipbuilders & Engineers, Tea Board of India, Geological Survey of India, Zoological Survey of India, Botanical Survey of India, Jute Corporation of India, National Test House, Hindustan Copper and the Ordnance Factories Board of the Indian Ministry of Defence. Demographics Population The demonym for residents of Kolkata are Calcuttan and Kolkatan. According to provisional results of the 2011 national census, Kolkata district, which occupies an area of , had a population of 4,486,679; its population density was . This represents a decline of 1.88% during the decade 2001–11. The sex ratio is 899 females per 1000 males—lower than the national average. The ratio is depressed by the influx of working males from surrounding rural areas, from the rest of West Bengal; these men commonly leave their families behind. Kolkata's literacy rate of 87.14% exceeds the national average of 74%. The final population totals of census 2011 stated the population of city as 4,496,694. The urban agglomeration had a population of 14,112,536 in 2011. , about one-third of the population, or 15 lakh (1.5 million) people, lived in 3,500 unregistered squatter-occupied and 2,011 registered slums. The authorised slums (with access to basic services like water, latrines, trash removal by the Kolkata Municipal Corporation) can be broadly divided into two groups—bustees, in which slum dwellers have some long term tenancy agreement with the landowners; and udbastu colonies, settlements which had been leased to refugees from present-day Bangladesh by the government. The unauthorised slums (devoid of basic services provided by the municipality) are occupied by squatters who started living on encroached lands—mainly along canals, railway lines and roads. According to the 2005 National Family Health Survey, around 14% of the households in Kolkata were poor, while 33% lived in slums, indicating a substantial proportion of households in slum areas were better off economically than the bottom quarter of urban households in terms of wealth status. Mother Teresa was awarded the Nobel Peace Prize for founding and working with the Missionaries of Charity in Kolkata—an organisation "whose primary task was to love and care for those persons nobody was prepared