1. Overview of the QNA database
The tables give both annual and quarterly data for all the OECD member countries, some other major economies and a number of groups of countries (zones). Data for countries are available in national currencies and, for the main components of GDP by Expenditure, they are also available in US dollars converted with Purchasing power parities as well as in volume and price indices. Data for zones are available in US dollars.
Tables are updated on a daily basis.
2. Historical data
Quarterly National Accounts data officially released by countries start in different years depending on the country’s practice, data availability and harmonisation with other relevant economic statistics. It is important to note that when countries change their methodology (for example in implementing the new SNA 2008), they usually provide at first a new set of accounts covering a limited period. Longer historical series are then normally made available over the following quarters.
In these cases of shorter time series, the OECD Secretariat, to ensure no loss of time series for users, estimates the missing data for the main expenditure components of GDP in order to publish historical data from Q1 1960 (where possible). The estimation is undertaken using the current systems of accounts and linking to older systems based on different methodology in order to obtain the longer time series.
The method used by the Secretariat to link two time series from two different methodologies is as follows: for each individual series, the ratio between the new methodology data and the old methodology data in the first common year is calculated. This ratio is then multiplied by old methodology series for the time period that data have not been provided. The same method is applied to both current and volume estimates data. Also historical growth rates are derived from estimated volume data.
All the datapoints estimated are flagged with an “E”.
To extract the historical series, the measures to be selected are: CARSA or VOBARSA for data expressed in national currency (respectively in current prices or volumes estimates) and CPCARSA or VPVOBARSA for data expressed in US dollars and GPSA or GYSA for quarter-on-quarter and year-on-year growth rates.
Nevertheless, due to missing annual long time series, data for some countries may start later: Chile, Czech Republic, Estonia, Hungary, Israel, Korea, Poland, Slovak Republic and Slovenia.
3. Annual and quarterly levels
Annual data are always expressed at annual level and are calculated by sum of the original quarters or average when it concerns population, employment series and also when they are derived from quarterly data at annual level.
Quarterly data are available at quarterly level and/or annual level depending on the country's practice. Canada, Japan, Mexico and the United States publish their data expressed at annual level. For these countries, quarterly data expressed at quarterly level have been derived by dividing national data by four.
The measure is composed of three parts giving information on valuation, level of quarterly data and seasonal adjustment (including for some countries adjustment for working days). For example, a series of chained volume estimates, expressed at quarterly level and seasonally adjusted will have the following measure: LNBQRSA.
Almost all OECD Member countries publish chained volume estimates but some countries still publish volume data at fixed constant prices. It is therefore recommended to select both VNBQR and LNBQR measures in order to extract original volume data and VNBQRSA and LNBQRSA in order to extract seasonally adjusted volume data.
-- Level of the quarterly data
-- Seasonal adjustment
5. Power code and decimals
Data are expressed in millions (national currencies, US dollars, hours worked), thousands (persons, jobs and full time equivalent) or unit (PPPs). Default power code and number of decimals can be changed by users.