1 Although any individual may develop a case of pinworms, the infection occurs most frequently in school children between 5 to 10 years of age.  Pinworm infections occur in all socioeconomic groups; however, human-to-human spread is favored by close, crowded living conditions. Spread among family members is common.
Before they start collecting, stamp collectors try to identify the types of stamps. These will help them segregate and sort stamps according to their classification. On its basic concept, there are three main classifications of stamps â special, commemorative, and definitive.
Semipostal stamps are stamps sold for a price that exceeds the postage value of the stamp. 1  The difference between the price and postage value (also known as the âdifferentialâ) less an offset for reasonable USPS costs, as determined by the USPS, is contributed to a specific cause.