With a population of 1.88 million in 2013, The Gambia List of countries by population. Its population density is 176.1 inhabitants per square kilometer (456.1 inhabitants per square mile). The overall List of countries by life expectancy is 64.1 years. The total fertility rate of 3.98 is one of the highest in the world. Since 1950, the United Nations (UN) estimated the birth rate exceeds the death rate. The Gambia Bureau of Statistics (GBOS) estimates the population of The Gambia is expected to reach 3.6 million in 20 years. The population of The Gambia has increased each census, starting with 315 thousand in 1963 to 1.8 million in 2013. The GBOS predicted the reason for the increase from 2003 to 2013 was more coverage in the latter census compared to the formers.. How many people was the population increased by in 2013 from 1963?