Tehran City Population, Household Size & National Primacy Share (1956-1972)_

Event_Log

1. ··1917Great Persian Famine and 1918 influenza pandemicCorrelationExpected causation

   Wartime allied grain requisitioning, blockade and disrupted trade routes during World War I trigger severe famine across Iran from 1917, compounded by the 1918-19 influenza pandemic, cholera and typhus under the weakened, occupied Qajar government; mainstream scholarship estimates roughly 2 million excess deaths (Mohammad Gholi Majd has argued for far higher tolls of 8-10 million, a figure not widely accepted among historians), devastating the rural agricultural labor force.

   Why this link: The 1917-19 famine and influenza pandemic killed an estimated ~2 million people, a demographic shock that forms part of the gap between Iran's rough 1900 population baseline and its 2006 level shown in this chart.

   Caveat: This chart shows only two snapshots (1900 and 2006); the famine's specific demographic toll is not visible in the data itself and cannot be isolated from a century of other births, deaths and migration.

   Lag: Immediate mortality shock (1917-19); reflected only in the multi-decade endpoint comparison.Source: Wikipedia — Persian famine of 1917-1919 (cross-checked against Encyclopaedia Iranica's "Influenza" article and academic literature on death-toll estimates)
2. 011956First national census of IranCorrelationExpected causation

   The General Department of Public Statistics conducts Iran's first modern population and housing census (1-16 November 1956) using 27,607 enumerators, recording a population of 18,954,704.

   Why this link: This 1956 count (recording a population of 18,954,704) is the foundational enumeration establishing Iran's modern population data series that this and all subsequent demographic charts build on.

   Caveat: Later WDI population figures are estimates/interpolations, not direct census counts for every year.

   Lag: ImmediateSource: Iran Data Portal (Syracuse University) -- Census