Population tables. of world cities. This article lists the most populous cities in the world defined according to a concept of city proper. A city proper is a locality defined according to legal or political boundaries and an administratively recognised urban status that is usually characterised by some form of local government. Cities proper and their boundaries and population data may not include suburbs. World Urbanization Prospects, a UN publication, defines population of a city proper as the population living within the admi
The mass of one cubic centimeter of copper is 8.96 grams, while the mass of the same amount of zinc is 7.13 grams. 1  A penny is made of copper and zinc. 2  Copper is heavier than zinc. 3  The cost of copper has been on the rise during the past couple of decades.
Metal is largest component of this cost: the penny has been composed of 97.5% zinc and 2.5% copper since 1982, and because the price of those metals fluctuates, so too does the cost of producing pennies. In 2005, the cost to the United States Mint to produce a penny was 0.97Â¢, which was just a smidge under a cent. In 2006, that year's pennies each cost about 1.23Â¢ to manufacture. Rises in metal prices, particularly of zinc, pushed the per-unit cost up to 1.7Â¢ in 2007. By 2012, production costs had risen to 2.41Â¢ per penny.