Year Sets - Modern U.S. stamps, anything issued after 1940, are in most cases collected by the year, since individual stamps sell for so little it is not worth a dealer’s time to sell the stamps individually.
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Yellowstone National Park - (Scott’s 744) the National Park honored on the five cent National Parks issue of 1934, featuring "Old Faithful"
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Yorktown Issue - (Scott’s 703) the bi-colored two-cent stamp of 1931 honoring the Battle of Yorktown and the surrender of General Cornwallis to General Washington.
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