Death rates in the 20th century is the ratio of deaths compared to the population around the world throughout the 20th century. When giving these ratios, they are most commonly expressed by number of deaths per 1,000 people per year. Many factors contribute to death rates such as cause of death, increasing the death rate, an ageing population, which could increase and decrease the death rates by birth rates, and improvements in public health, decreasing the death rate. According to the CIA World Factbook, , the global crude death rate is 7.99 deaths/1,000 population. The crude death rate represents the total number of deaths per year per thousand people. Comparatively, the crude death rate in the year 1900 was 17.2 deaths/1,000 population and 9.6 deaths/1,000 population in 1950 in the United States. Highest crude death rates worldwide The World Fact Book Cause of death Throughout the 20th century in the developed world, the leading causes of death transitioned from infectious diseases such as influenza, to degenerative diseases such as cancer or diabetes. In 1900, the leading cause of death in the United States was influenza with 202.2 deaths per 100,000 people followed by tuberculosis with 194.4, which is a curable illness today. In the middle of 20th century America, the leading cause of death was heart disease with 355.5 deaths per 100,000 followed by cancer at 139.8 deaths per 100,000. Although death rates dropped significantly in the latter part of the 20th century, the leading killers are still constant. The United States saw 192.9 people per 100,000 die from heart disease in 2010 followed by cancer with 185.9 people per 100,000. An estimated 70 to 120 million people died from famine in the 20th century, of whom over half died in China. Malnutrition and hunger was also a leading cause of the global infant mortality and child mortality. The world population in the 20th century experienced a large amount of death due to two major world wars. World War II was responsible for the most war related deaths in the 1900s with a death toll between 40,000,000 and 85,000,000 deaths. Other predominate wars in the 1900s include World War I with up to 22,000,000 deaths, the Russian Civil War with up to 9,000,000 deaths, the Afghan Civil War with up to 2,000,000 deaths, and the Mexican Revolution with up to 2,000,000 deaths. Several other major wars took place in the