National income and product accounts (or, national income accounts, for short) are an accounting system used to measure of aggregate economic activity.An economic indicator is a statistic about an economic activity. Economic indicators allow analysis of economic performance and predictions of future performance. One application of economic indicators is the study of business cycles. Economic indicators include various indices, earnings reports, and economic summaries. Examples: unemployment rate, quits rate, housing starts, Consumer Price Index (a measure for inflation),Consumer Leverage Ratio, industrial production, bankruptcies, Gross Domestic Product, broadband internet penetration, retail sales, stock marketprices, money supply changes.