1955 Rate of Natural Increase

In 1955, the world’s rate of natural increase (RNI)—the difference between birth and death rates, excluding migration—was at one of its historical highs, averaging around 1.8% per year globally. This surge was largely driven by dramatic declines in mortality rates, especially infant and child mortality, due to advances in medicine and public health, while birth rates remained high in many regions. Asia and Africa experienced the highest RNIs, with many countries in Sub-Saharan Africa and South Asia exceeding 2.5% per year, reflecting both high fertility and improving survival rates. In contrast, Europe’s RNI was much lower, often below 1%, as both birth and death rates had declined earlier, leading to slower population growth. Latin America and the Middle East also saw high RNIs, generally between 2% and 3%. Within continents, there was considerable variation: for example, Japan’s RNI had already fallen below 1.5% due to rapid demographic transition, while countries like Nigeria and Pakistan had RNIs above 2.5%. The United States and Canada had moderate RNIs of around 1.6%–1.7%, reflecting the post-war baby boom but also declining death rates. Thus, in 1955, the global demographic landscape was marked by stark contrasts, with developing regions experiencing rapid population growth, while more developed countries saw much slower increases.

Data from US Census International Database