33 U.S.C. § 3004

(a) Grades The commissioned grades in the commissioned officer corps of the Administration are the following, in relative rank with officers of the Navy: (1) Vice admiral. (2) Rear admiral. (3) Rear admiral (lower half). (4) Captain. (5) Commander. (6) Lieutenant commander. (7) Lieutenant. (8) Lieutenant (junior grade). (9) Ensign. (b) Grade distribution The Secretary shall prescribe, with respect to the distribution on the lineal list in grade, the percentages applicable to the grades set forth in subsection (a). (c) Annual computation of number in grade (1) In general Not less frequently than once each year, the Secretary shall make a computation to determine the number of officers on the lineal list authorized to be serving in each grade. (2) Method of computation The number in each grade shall be computed by applying the applicable percentage to the total number of such officers serving on active duty on the date the computation is made. (3) Fractions If a final fraction occurs in computing the authorized number of officers in a grade, the nearest whole number shall be taken. If the fraction is one-half, the next higher whole number shall be taken. (d) Temporary increase in numbers The total number of officers authorized by law to be on the lineal list during a fiscal year may be temporarily exceeded if the average number on that list during that fiscal year does not exceed the authorized number. (e) Positions of importance and responsibility Officers serving in positions designated under section 3028(a) of this title and officers recalled from retired status shall not be counted when computing authorized strengths under subsection (c) and shall not count against those strengths. (f) Preservation of grade and pay No officer may be reduced in grade or pay or separated from the commissioned officer corps of the Administration as the result of a computation made to determine the authorized number of officers in the various grades.