This article concludes with the interesting fact that the only annual drop in U.S. population during the past century “occurred between July 1917 and July 1918, when the country was at war,” implying a military cause for the decline. Indeed, the honored dead of the First World War did total 116,708. However, you missed the far-more-serious cause of death responsible for the population anomaly: the great influenza, which killed 675,000 Americans, mostly in 1918.

John Bernhart
New Tripoli, Pa.

Both events certainly contributed to the population decline during the year ending July 1, 1918. However, the flu caused most of its mortality in the United States during the fall of 1918 and the spring of 1919. Interestingly, the U.S. population rose by 1.3 million between July 1, 1918, and July 1, 1919. —B. Harder