Kolkata has always been a city of migrants. They are the people who have made the city so large. In the first half of the 20th century the largest group of migrants were the working-class people from Bihar. After 1947, they were overtaken in numbers by the refugees from East Pakistan. A comparatively lesser number of people from the surrounding areas have migrated to the city, because a huge population commutes to the city for work and returns to their villages. They are not counted in the census data for Kolkata. The promise of a better quality of life may have been an initial attraction for the migrants, but bulk of the poorer sections soon realized that poverty in Kolkata was as severe and dehumanising as in the villages they left behind. However, many of them found opportunities of income in the urban economy. Some of them managed a place in industry, because of the preferential treatment they got as a result of people in their community vouching for them. A 1976 survey revealed that the proportion of workers from outside West Bengal were 71% in the jute industry, 58% in textile mills and 73% in iron and steel units. The Chamars from the Hindi heartland, many of whom work in the leather industry, have been here for more than a century. As per the 1951 census, only 33.2% of Kolkata's inhabitants were city-born. The rest, including a small group of foreigners, were migrants. 12.3% came from elsewhere in West Bengal, 26.3% from other states in India and 29.6% were refugees from East Pakistan.