In 1917 and 1918, approximately 24 million men living in the United States completed a World War I draft registration card. Three registrations were conducted between 1917 and 1918. The first was held on June 5, 1917 for men between the ages of 21 and 31. The second was held June 5, 1918 for men who turned 21 since the first registration. A third commenced on September 12, 1918 for men between 18 and 45. These registration cards represent approximately 98% of the men under the age of 46. The total U.S. population in 1917-1918 was about 100 million individuals. In other words, close to 25% of the total population is represented in these records.
