The key graphs summarise macroeconomic and financial market trends in New Zealand. The Consumers Price Index (CPI) measures changes to the prices of the consumer items New Zealand households buy, and provides a measure of household inflation. Data is available from 1916. Since March 1999, the Reserve Bank has used the Official Cash Rate (OCR) as its tool for implementing monetary policy. By setting the OCR, the Reserve Bank is able to influence short-term interest rates such as the 90-day bank bill rate, as well as long-term interest rates and the foreign exchange rate. Data is available from 1999. The trade weighted index (TWI) measures the value of the New Zealand dollar (NZD) against New Zealand's major trading partners. It is the Reserve Bank's preferred summary measure for capturing the medium-term effect of exchange rate changes on the New Zealand economy and inflation. Data for the nominal TWI (17) is available from 1984. Gross domestic product (GDP) represents the value of all goods and services produced in New Zealand. The growth in real GDP is New Zealand's official measure of economic growth. Real GDP excludes the effects of changing prices (i.e. inflation). Data is available from 1990. The Balance of Payments (BoP) statistics set out a country’s transactions with the rest of the world. The current account records New Zealand's transactions in goods, services, income, and current transfers with the rest of the world. More simply, the current account measures what a country earns offshore minus what it spends offshore. Data is available from 1998. The average floating and two year fixed mortgage rates is the rate advertised to new customers by banks for residential home loans. Data is available from 1998. Housing is a central part of the New Zealand economy and accounts for around half of the assets of New Zealand households. Data is available from 1979. Household debt comprises mortgage loans, consumer loans such as credit cards, and student loans. Data is available from 1998. The unemployment rate reflects labour market conditions. It measures the proportion of people in the labour force who are unemployed. Data is available from 1986.