These are lists of regions and countries by their estimated real gross domestic product (GDP)
in terms of purchasing power parity
(PPP), the value of all final goods and services produced within a country/region in a given year. GDP dollar (international dollar
) estimates here are derived from PPP estimates.
In the absence of sufficient data for nearly all economies until well into the 19th century, past GDP cannot be calculated, but at best only roughly estimated. In a first step, economic historians try to reconstruct the GDP per capita
for a given political or geographical entity from the meagre evidence. This value is then multiplied by estimated population
size, another determinant for which as a rule only little ancient data is available.
A key notion in the whole process is that of subsistence
, the income
level which is necessary for sustaining one's life. Since pre-modern societies
, by modern standards, were characterized by a very low degree of urbanization
and a large majority of people working in the agricultural sector
, economic historians prefer to express income in cereal
units. To achieve comparability over space and time, these numbers are then converted into monetary units such as International Dollars, a third step which leaves a relatively wide margin of interpretation.
The formula thus is: GDP (PPP) = GDP per capita (PPP) x population size
It should be stressed that, historically speaking, population size is the far more important multiplier in the equation.... Read More