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More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
In 2010, opiate painkllers, such as morphine, OxyContin®, and Vicodin®, were tied to almost 60% of drug overdose deaths.
Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.