DOD Personnel, Workforce Reports & Publications. This web portal provides various strength accounting reports: https://www.dmdc.osd.mil/appj/dwp/dwp_reports.jsp
The Population Representation in the Military Services (Pop-Rep) reports describe the characteristics of U.S. military personnel in order to provide comprehensive, reliable and consistent data tabulations on military personnel. They can be accessed via the Office of the Under Secretary for Personnel and Readiness website: https://prhome.defense.gov/M-RA/Inside-M-RA/MPP/Accession-Policy/Pop-Rep/.
Defense Casualty Analysis System (DCAS). The central objective of DCAS is to collect and maintain U.S. casualty information on war fighters who have fallen in global or regional conflicts involving the United States. https://dcas.dmdc.osd.mil/dcas/pages/main.xhtml
Demographic Profiles. These annual reports provide a detailed look at the people who make up the military community, from active-duty and reserve members to their spouses and children. Information for all services includes gender, race, age, education, family members, pay grades, installation populations and other important facts. https://www.militaryonesource.mil/reports-and-surveys/demographic-profiles