The 'Units' value displayed in each province is a modifier which is based on the province's population. This modifier affects manpower, production income, toll income, and the value of trade the province contributes to a centre of trade.
Where Colony Level is equal to the population divided by 100 and rounded down to an integer.
The value is has a maximum of 2.0 which occurs when the population is 201,000 or higher.
For cities (IN 3.1):
For the IN expansion patch 3.1, the population effect is capped at a population of 101,000 and 'distant overseas' provinces are capped at 1.0 Units.
This is displayed rounded to the nearest tenth but the actual rounding is done to the thousandth (3rd decimal point). That means that a city with population 15,000 has exactly the same production with a city of population 15,099, assuming same base taxes.
Yamashiro with a population: 97,854 and base tax: 8
which after rounding becomes 2.368 and is displayed as 2.4
Population growth details the rate at which populations increase. The value given in the province view is the fraction at which a population will increase over the next ten years, assuming no changes to the conditions.
Various conditions can have an effect on population growth
|Support nomad raids||+3%|
|Allow nomad raids||+1%|
|Improve Frontier Defences||+5%|
|Enact Settlement Policy||+10%|
|Regulation of the Medical Profession||+10%|
|Centre of Trade||+1%/100 value (rounded down)|