Table 3.

Sociodemographic characteristics of the analysis sample of the China Health and Nutrition Survey

Characteristics	1991 (n 9251)		2000 (n 10 491)		2009 (n 9912)		2015 (n 14 549)
	n	%	n	%	n	%	n	%
Age group, years
18–49	6654	71·9	6804	64·9	4894	49·4	6372	43·8
50–64	1750	18·9	2351	22·4	3232	32·6	5063	34·8
≥65	847	9·2	1336	12·7	1786	18	3114	21·4
Gender
Male	4453	48·1	5107	48·7	4759	48	6818	46·9
Female	4798	51·9	5384	51·3	5153	52	7731	53·1
Region
Rural	6100	65·9	7180	68·4	6821	68·8	8949	61·5
Urban	3151	34·1	3311	31·6	3091	31·2	5600	38·5
Education level
Primary/illiterate	5396	58·3	5240	50	4226	42·6	4808	33·1
Middle school	2454	26·5	3036	28·9	3264	32·9	4620	31·8
High/above	1401	15·1	2215	21·1	2422	24·4	5094	35·1
Household income level
Low	3078	33·3	3497	33·3	3303	33·3	4752	33·3
Medium	3077	33·3	3497	33·3	3305	33·3	4757	33·4
High	3078	33·3	3497	33·3	3304	33·3	4746	33·3
Urbanicity index
Low	3052	33·1	3487	33·2	3302	33·3	4753	33·3
Medium	3102	33·6	3517	33·5	3292	33·2	4746	33·3
High	3079	33·4	3487	33·2	3318	33·5	4756	33·4

Data are expressed as n (%).