Generally it can be said that inflation is a measure of a general increase of the price level in an economy, as represented typically by an inclusive price index, such as the Consumer Price Index in a nation. The term indicates many individual prices rising together rather than one or two isolated prices, such as the price of gas in an otherwise calm price environment. The inflation rate is typically expressed as an annual growth rate in prices (again, as measured by an index) even if measured over a shorter period of time. For example, if a radi o report states that "consumer prices rose at an inflation rate of six percent last quarter," that would typically mean than the Consumer Price Index for All Urban Consumers (the most quoted index) rose over the last three months at an annualized rate of around four percent, and the press would generally refer to the current inflation rate as around four percent. The term deflation refers to a general decline  in prices or the price level as measured by an inclusive price index and, again, is not a reference to isolated price declines, like natural gas declining in price, in an otherwise stable price environment.