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.
While brass is an alloy of copper and zinc, bronze is an alloy consisting mainly of copper, combined most often with tin, but at times also with other metals.