July holds special significance for US philatelists. It was this month in 1963 when the U.S. Postal Service first introduced the five-digit ZIP code to help speed mail to the correct address. The new system reflected the change in the nation from an agricultural economy and the resulting explosion in business mail. July also marks the issuing in 1847 of the first official U.S. postage stamps a 5-cent stamp honored Benjamin Franklin and one, costing 10-cents, for George Washington. Today, there are nearly 38-thousand post offices across the nation.