The crude birth rate (CBR) and crude death rate (CBR) are statistical values that can be used to measure the growth or decline of a population.
The crude birth rate and crude death rate are both measured by the rate of births or deaths respectively among a population of 1,000. The CBR and CDR are determined by taking the total number of births or deaths in a population and dividing both values by a number to obtain the rate per 1,000.
For example, if a country has a population of 1 million, and 15,000 babies were born last year in that country, we divide both the 15,000 and 1,000,000 by 1,000 to obtain the rate per 1,000. Thus the crude birth rate is 15 per 1,000.
The crude birth rate is called "crude" because it does not take into account age or sex differences among the population. In our hypothetical country, the rate is 15 births for every 1,000 people, but the likelihood is that around 500 of those 1,000 people are men, and of the 500 who are women, only a certain percentage are capable of giving birth in a given year.
Crude birth rates of more than 30 per 1,000 are considered high, and rates of less than 18 per 1,000 are considered low. The global crude birth rate in 2016 was 19 per 1,000.
In 2016, crude birth rates ranged from 8 per 1,000 in countries such as Japan, Italy, Republic of Korea, and Portugal to 48 in Niger. The CBR in the United States continued trending down, as it did for the entire world since peaking in 1963, coming in at 12 per 1,000. By comparison in 1963, the world's crude birth rate hit more than 36.
Many African countries have a very high crude birth rate, and women in those countries have a high total fertility rate, meaning they give births to many children in their lifetime. Countries with a low fertility rate (and low crude birth rate of 10 to 12 in 2016) include European nations, the United States, and China.
The crude death rate measures the rate of deaths for every 1,000 people in a given population. Crude death rates of below 10 are considered low, while crude death rates above 20 per 1,000 are considered high. Crude death rates in 2016 ranged from 2 in Qatar, the United Arab Emirates, and Bahrain to 15 per 1,000 in Latvia, Ukraine, and Bulgaria.
The global crude death rate in 2016 was 7.6, and in the United States, the rate was 8 per 1,000. The crude death rate for the world has been on the decline since 1960 when it came in at 17.7.
It has been falling around the world (and dramatically in developing economies) due to longer life spans brought about by a better food supplies and distribution, better nutrition, better and more widely available medical care (and the development of technologies such as immunizations and antibiotics), improvements in sanitation and hygiene, and clean water supplies. Much of the increase in world population over the last century overall has been attributed more to longer life expectancies rather than an increase in births.