In 1958 the Army added two grades to the NCO ranks. With the addition of these grades, the ranks of the NCO were corporal, sergeant, staff sergeant, sergeant first class, master sergeant and sergeant major.
DRI is the general term for a set of reference values used to plan and assess nutrient intakes of healthy people. These values, which vary by age and gender, include: Recommended Dietary Allowance (RDA): average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people.
For adults, the recommended daily value of vitamin D is 600 International Units (IU) or 15 micrograms (mcg). It is likely that a doctor will recommend between 400 and 1,000 IU per day to supplement your diet for a short period of time.