According to the CIA World Factbook, as of July 2012[update], the global crude death rate is 7.99 deaths/1,000 population.
Although death rates dropped significantly in the latter part of the 20th century, the leading killers are still constant.
Recently and most notably, the years immediately after World War II saw an explosion in fertility rates called the Baby Boom because the returning soldiers and displaced people started new families.
Death rates were significantly lower during the baby boom and thus populations increased substantially.
The World Bank predicts a dramatic decrease in population size from the increase in death rates over the next decade.
During the 20th century, an enormous improvement in public health led to an overall decrease in death rates.
In 1999, at the end of the century, the infant mortality rate in the United States declined more than 90% to 7.2 deaths per 1,000 live births.