Methodology

The number 0 or 0.0 means zero or less than half the unit shown.

The abbreviation "na" means "not available" or "not applicable".

Simple total: Sum of all available data values without filling for missing data.

Shares: The value for one variable for a specific country divided by the aggregate (all countries) value for that variable (available or calculated as a simple total for all countries).

Ranks: For some of the numerical variables, the data for the same year and for the top 25 countries are arranged in numerically ascending or descending order, depending on the variable selected. This arrangement makes it possible to compare their relative position.

The data are formatted according to the metric system methodology. The International System (IS) of measures is used for numerical data. Whole numbers are separated from decimals by a dot (or a comma), while an empty space separates whole numbers grouped in threes (e.g. 999 999.999 or 999 999,999).

k stands for thousands.