Rare, probably, because so many of them are returned from Iraq and Afghanistan in boxes.

From WJLA:

In a rare all-military naturalization ceremony, the Pentagon will give 30 service members citizenship of the United States.

The new citizens represent the 17 countries of: Belize, Bolivia, Canada Colombia, Cuba, Ethiopia, Ghana, Guyana, Jamaica, Kenya, Mexico, Nigeria, Pakistan, Panama, Philippines, Peru, and the United Kingdom.

The service members are from the Army, Navy, Air Force and Marines, and include members of the National Guard and Reserve.