Table 1.

Social demographic characteristics of participants.

	Household Registration				Economic Region
Items	Urban		Rural		Eastern		Central		Western
	N	%	N	%	N	%	N	%	N	%
Gender
Male	2343	42.14	2375	48.88	2082	43.43	1705	49.49	797	43.7
Female	3217	57.86	2484	51.12	2712	56.57	1740	50.51	1027	56.3
Marital status
Married	3310	59.53	1776	36.55	2405	50.17	1672	48.53	782	42.87
Unmarried	2199	39.55	3042	62.61	2351	49.04	1740	50.51	1026	56.25
Divorced	46	0.83	34	0.7	33	0.69	31	0.9	11	0.6
Widowed	5	0.09	7	0.14	5	0.1	2	0.06	5	0.27
Age
<60	5508	99.06	4831	99.42	4763	99.35	3416	99.16	1808	99.12
>60	52	0.94	28	0.58	31	0.65	29	0.84	16	0.88
Monthly income (CNY)
<3000	982	17.66	1639	33.73	1037	21.63	985	28.59	533	29.22
3000~5000	1265	22.75	1374	28.28	1175	24.51	890	25.83	502	27.52
5000~10,000	2312	41.58	1534	31.57	1921	40.07	1176	34.14	609	33.39
10,000~30,000	913	16.42	289	5.95	600	12.52	367	10.65	161	8.83
30,000~50,000	72	1.29	15	0.31	48	1	21	0.61	15	0.82
≥50,000	16	0.29	8	0.16	13	0.27	6	0.17	4	0.22
Education
Junior high school or below	65	1.17	162	3.33	102	2.13	76	2.21	40	2.19
Senior high school	542	9.75	837	17.23	655	13.66	457	13.27	229	12.55
Undergraduate or college graduate	4235	76.17	3536	72.77	3527	73.57	2605	75.62	1377	75.49
Postgraduate or above	718	12.91	324	6.67	510	10.64	307	8.91	178	9.76