In the United States, cigarette use has declined from nearly 42% of the population in 1965, to nearly 19% among adults in 2011. However, cigarette smoking remains the most common form of tobacco used in the United States that approximately 43.8 million adults smoke cigarettes. In 2011, approximately 22% of men and 17% of women were cigarette smokers. Education has a strong relationship with cigarette smoking rates. People with a higher education have a lower smoking rate. Therefore, more people smoke in the Midwest, about 22%, and smoke less in the West, about 15%, as there are higher levels of education in the West, where the major cities are located. Figure 8, on the next page, shows annual per capita cigarette consumption worldwide and identifies the different levels. Although cigarette smoking is the most common form of tobacco used, its activity does not end with cigarettes alone. Other forms of tobacco are also common around the world. A survey conducted by the U.S. Substance Abuse and Mental Health Administration in 2010 found that 8.9 million people used smokeless or spit tobacco, 13.2 million used cigars, and 2.2 million people smoked tobacco in pipes. Around the world, approximately 852 million people consume tobacco in its various forms. This concerns 41% of the world's male population and only 5% of the female population. Additionally, China and India both have the largest populations of tobacco smokers, with 301 million and 275 million smokers, respectively. Tobacco and young people: tobacco, in all its forms, is widely spread among young people. According to government surveys, although smoking, dipping snuff, chewing and spitting tobacco are common among most adolescents, they are more common among young males. Figure 9 breaks down the percentage… center of paper… graph. Consequently, by damaging the lungs and destroying some of their functions, smoking leads to what is known as smoker's cough. Smoker's cough: Smokers usually have smoker's cough which is the result of inhaling irritable particles and chemicals from tobacco smoke. . This "smoker's cough" clears out mucus and irritants found in the lungs. It results from the delay of the cilia, as tobacco smoke destroys them, which are used to sweep harmful material from the lungs. The effect of smoking on cilia is shown in Figure 15. Some smoke particles remain in the lungs and mucus remains in the airways; therefore, when the smoker coughs, all irritable particles are eliminated from the lungs. Smoker's cough also eliminates toxins and tar present in the lungs and is therefore considered a defense mechanism because it carries out the work of the cilia.