Economic analysis provides insight into how markets operate and offer methods for attempting to predict future market behaviour in response to events, trends and cycles. It is also used by governments to determine tax rates and evaluate the financial health of the nation or state. In finance, economics and accounting the important fundamental dimensional analysis is most commonly referred to in terms of the distinction between stocks and flows. Most generally, dimensional analysis is used in interpreting various financial ratios, economics ratios and accounting rations. In interest rates are often expressed as a percentage but more properly percent per annum which has dimensions of 1/years. In economics, bond duration P/E ratio, debt-to GDP ratio and velocity of money also has units of years.