Table 3. Demographic characteristics of deployed U.S. military personnel who completed the Qatar Clinic health screening questionnaire Feb 2005 to Feb 2006, N = 15,463^*.

Characteristic	Frequency, n	Percent
Mean age, years (range)	28.6	(19–54)
Sex
Male	13,170	86.3
Female	2,090	13.7
Rank
E1–E3	2,199	14.7
E4–E6	10,547	70.5
E7–E9	946	6.3
O1–O3	652	4.4
O4–O6	488	3.3
Chief Warrant Officer	122	0.8
Country of deployment
Afghanistan	2,420	15.7
Iraq	11,175	72.3
Kuwait	1,584	10.2
Other	57	0.4

^*denominator for characteristic varies due to missing values.