Table 1: Demographic, social, and service characteristics of the Chinese air force personnel, responding the first questionnaire: ( ).

Variables Aircrew ( ) Ground personnel ( ) value

Age <0.001
 <25 232 (28.4)2911 (69.8)
 25–30 242 (29.6)951 (22.8)
 >35 344 (42.0)308 (7.4)
Race0.16
 Han race 793 (96.9)3999 (95.9)
 Minority 25 (3.1)171 (4.1)
Marital status<0.001
 Single 317 (38.7)3236 (77.6)
 Married 465 (56.8)746 (17.9)
 Separated/divorced 36 (4.5)188 (4.5)
Education<0.001
 Less than high school1 (0.1)575 (13.8)
 High school 30 (3.7)2144 (51.4)
 College graduate 774 (94.6)1384 (33.2)
 Postgraduate 13 (1.6)67 (1.6)
Years of service<0.001
 <4 120 (14.7)2052 (49.2)
 4–16 479 (58.5)2001 (48.0)
 >16 219 (26.8)117 (2.8)
Rank<0.001
 Officer 757 (92.4)313 (7.5)
 Enlisted 61 (7.4)3857 (92.5)