The world population is the sum of all humans on the earth. The united States census bureau (uscb) estimates that the world population exceeded 7 billion on march 12 2012. The world's population is growing by nearly 80 million people per year. While population growth rates have slowed since THIER peak in the 1960s the number being added to population each year continue to be huge in part because of the growth in the number of people of reproductive age. At current rates of birth and death the world population is oin a trajectory to double in 49 years.
Basic Definition & Terminologies:
Demography:
The study of population statistics and trend such as birth death and age structure.
Birth rate or Crude birth date:
The number of live birth per 1000 individuals annually within a population.
Death rate or Crude date rate:
The number of death perb1000 individual annually within a population.
Growth rate:
The number of person added to oor subtracted from a population in a year due to natural increase and net migration expressed as a percentages of the populations at the beginning of the time pere.
Or
The average annual percent change in the population resulting from a sulphur or deficitvof birth over deaths and the balance of migrants entering and leaving a country. The rate may be positive or negative.
Growing rate=birth%-death% +or -net migration.
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