The CPI takes a constant basket of goods and sees how the price changes from year to year. If the price of the basket of goods increases, then there is price inflation. If the price of the basket of goods decreases, then there is deflation.
Copper and tin mainly make up bronze but other elements include phosphorus, manganese, silicon and aluminium.
Bronze is a copper and tin alloy, but the term is also used for a variety of copper alloys, some of which do not contain tin at all. The use of bronze has been reported since the earliest Mesopotamian and Egyptian civilisations in the manufacture of tools and weapons.