The said plot shall be available, to the extent such space is available, without charge or cost for the burial of persons who have served in the army, navy, or marine corps in the United States, in the Spanish-American war, Philippine insurrection, or the Chinese Relief Expedition, or who served in any said branches of said service at any time between April 21, 1898 and July 4, 1902 and any veteran as defined in RCW 41.04.007.