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The horizontal fraction bar was introduced by the Arabs.
The senior population grows every year. Seniors older than 65 years of age now comprise more than 13% of the total population. However, women outlive men. In the 85-and-over age group, there are only 45 men to every 100 women.
In ancient Rome, many of the richer people in the population had lead-induced gout. The reason for this is unclear. Lead poisoning has also been linked to madness.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
During the twentieth century, a variant of the metric system was used in Russia and France in which the base unit of mass was the tonne. Instead of kilograms, this system used millitonnes (mt).