Final answer:
The number of live births per 1000 people in the population per year is termed the crude birth rate. It is used to calculate population growth by subtracting the crude death rate from the crude birth rate and then expressing the net number as a percentage.
Step-by-step explanation:
The number of live births per 1000 people in the population per year is known as the crude birth rate. This measure, alongside the crude death rate, is vital in calculating the overall growth of a population.
For example, if a country has a crude death rate of 15 per 1,000 people per year and a birth rate of 35 per 1,000 per year, the net population growth would be the difference between the two, which is 20 per 1,000 people per year (35 births - 15 deaths). To express this growth as a percentage, we would divide the net number of people added (20) by the initial population (1,000) and then multiply by 100, resulting in a 2% population growth rate per year.