The Second Continental Congress adopted the Stars and Stripes as the nation's flag on June 14, 1777.
While most Americans celebrate the Fourth of July as Independence Day, fewer fly Old Glory on Flag Day, which originated with an observance at Philadelphia's Independence Square about 1883, The Christian Science Monitor observes.
President Woodrow Wilson proclaimed June 14 National Flag Day in 1916 and Congress made it official in 1949.
Valley Forge Flag Co. spokesman Chris Binner told the Monitor 2011 has been a "fairly patriotic year," with sales up between 10 percent and 20 percent.
U.S. flag sales took off in 2001 and have remained stronger than they were before the Sept. 11 terror attacks on New York's World Trade Center towers and the Pentagon outside Washington. Sales of the Stars and Stripes traditionally increase near Memorial Day and July 4, and this year are expected to soar for the 10th anniversary of the terror attacks, the Monitor said.