Black women are enlisting in the military at far higher rates than are white or Hispanic women, and they now represent nearly a third of all the women in the armed forces, a new study by the Pew Research Center has found.

The study found that of the 167,000 enlisted women in the military, 31 percent are black, twice their percentage in the civilian female population. Black men represent about 16 percent of the male enlisted population, roughly equal to their proportion in the civilian population.

White women, by comparison, represent 53 percent of women in the military, while accounting for 78 percent of the civilian female population.

The study, which is based on demographic data collected by the Defense Department, confirmed what military experts have known for years: that black women are a crucial source of new recruits for the armed forces, especially for the Army and the Air Force.