Cairo is the economic center of Egypt, with two-thirds of the country's gross national product generated in the greater metropolitan area. Industrialization, which began in the nineteenth century, grew rapidly following the 1952 revolution and revolved primarily around textiles (based on Egypt's traditional economic mainstay, long-staple cotton) and food processing. Other industries include iron and steel production and consumer goods. Today the majority of Cairo's work force is employed in service sector jobs, especially in government, financial services, and commerce. The tourism industry is a major source of revenue for the country, along with weapons sales, petroleum, and Suez Canal tariffs (following nationalization of the canal on July 26, 1956). Foreign aid from other countries is also an important source of income.
Although government agricultural subsidies, cheap public transportation, and low-cost medical care help keep Cairo's cost of living relatively low, the average Cairene still struggle to make ends meet, often holding down two or more jobs, or going overseas to find work and send money home. The poorest are forced to send their children to work as early as eight or nine years of age, often in "sweatshops" producing manufactured goods.