The practice of smoking can be dated to as early as 5000 BC and has been recorded in many different cultures across the world. Early smoking evolved in association with religious ceremonies; as offerings to deities, in cleansing rituals or to allow shamans and priests to alter their minds for various religious purposes. After the European exploration and conquest of the Americas, the practice of smoking tobacco quickly spread to the rest of the world. Smoking has negative health effects because smoke inhalation inherently poses challenges to various physiologic processes such as respiration. Diseases related to tobacco smoking have been shown to kill approximately half of the long term smokers when compared to average mortality rates faced by non-smokers. A 2007 report states that each year, about 4.9 million people worldwide die as a result of smoking. It is among the leading causes of many diseases such as lung cancer, heart attacks, erectile dysfunction, and birth defects. The health hazards of smoking have caused many countries to institute high taxes on tobacco products, run ads to discourage use, limit ads that promote use, and provide help with quitting for those who do smoke.