More measurements of population

Net migration rate: the difference between the number of persons entering and leaving a country during a year.

 An excess of persons entering the country is net immigration.

Why do people migrate?

Push forces

-        civil war

-        environmental degradation

-        unemployment or undenemployment

-        religious or ethnic persecution

pull forces

-        better enconomic opportunity

-        better health services

-        religious freedom

-        political freedom

total Fertility Rate (TFR)

TFR: average number of children born per women.

For a population to remain the same, the TFR must be 2.1

Higher than 2.1: population rises

Lower than 2.1: population falls

World TFR 2.47 (2.54 two years ago)

US TFR: 2.06

Nigeria TFR: 5.38

Japan TFR: 1.39