Table 1 Characteristics of survey participants with and without missing data in 2005, 2009 and 2013

Final sample size

26

3102

125

5039

150

5119

Age (Mean ± SD)

34 ± 12.3

40.9 ± 13.0

31.6 ± 8.8

38.3 ± 11.4

31.1 ± 9.3

37.3 ± 11.9

Sex (% Male)

46.1

48.5

17.2

41.2

14.8

45.2

Education (% Tertiary)

19.2

20.4

28.7

23.9

39.6

29.2

Employment (% Employed)

38.5

56.7

57.4

60.3

58.4

65.1

Geographical location (% Urban)

69.2

50.5

62.3

52.9

40.3

49.0