1. Overview of the QNA database
The tables present Quarterly National Accounts 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 for GDP 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, 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 OECD 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, in US dollars. Also historical growth rates are derived from estimated volume data.

All the datapoints estimated are flagged with an “E”.

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 byt the OECD by dividing national data by four.

 

4. Combined unit of measure
The combined unit of measure is composed of the following information:

- Price base

V: Current prices
L: Chain linked volume
LR: Chain linked volume (rebased)
Q: Constant prices
D: Deflator
DR: Deflator (rebased) 

- Adjustment

Y: Calendar and seasonally adjusted
N: Neither seasonally nor calendar adjusted 

- Unit of measure

PC: Percentage change
PD: Percentage points
XDC: National currency
USD: US dollar
USD_PPP: US dollars, PPP converted
USD_PPP_PS: US dollars per person, PPP converted
IX: Index 

- Transformation

G1 : Growth rate, period on period
GO1: Contribution to growth rate, period on period
GY: Growth rate, over 1 year
GCM: Cumulative growth rate since base period
LA: Annual levels
N : Non transformed data 

- Unit multiplier

3: Thousands
6: Millions

- Price reference year (if applicable)