Table 1.

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

	2005		2009		2013
	Missing	No missing	Missing	No missing	Missing	No missing
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

Abbreviation: SD standard deviation