Table 1. Sample size and information on age, gender, academic career, children under junior high school age, and elderly people over 65.

	Year	Japan		The United States		The United Kingdom		Italy		China
		Whole the participants	Men and Women only	Whole the participants	Men and Women only	Whole the participants	Men and Women only	Whole the participants	Men and Women only	Whole the participants	Men and Women only
Size of full samples (including inattentive respondents) in each year	2020	525	–	446	–	443	–	536	–	902	–
	2021	446	–	439	–	426	–	423	–	649	–
	2022	443	–	432	–	419	–	420	–	672	–
Size of valid samples in each year	2020	400	396	399	394	402	401	476	473	518	510
	2021	392	390	399	392	399	394	394	392	421	415
	2022	393	387	398	389	397	393	394	387	432	423
Size of valid samples in each year	2020 only	241	239	247	242	168	168	411	408	478	470
	2021 only	81	81	195	189	100	96	150	150	361	355
	2022 only	142	138	275	267	194	190	164	159	397	388
	2020 and 2021	60	60	81	81	96	95	14	14	28	28
	2020 and 2022	0	0	0	0	0	0	0	0	3	3
	2021 and 2022	152	152	52	51	65	65	179	177	23	23
	2020, 2021, and 2022	99	97	71	71	138	138	51	51	9	9
Size of unique valid samples	2020–2022	775	767	921	901	761	752	969	959	1299	1276
Age is presented as the mean (SD).	2020	35.9 (10.3)	35.9 (10.3)	36.2 (12.7)	36.4 (12.8)	35.5 (12.6)	35.5 (12.7)	34.1 (11.5)a	34.1 (11.5)	23.3 (6.4)	23.2 (6.3)
	2021	39.6 (10.1)	39.6 (10.1)	36.1 (13.2)	36.2 (13.2)	39.2 (12.9)	39.4 (12.9)	26.7 (7.4)	26.7 (7.4)	21.9 (4.0)	21.9 (4.0)
	2022	41.4 (10.6)	41.5 (10.6)	37.5 (14.1)	37.7 (14.2)	41.2 (12.9)	41.3 (12.9)	28.3 (8.0)	28.4 (8.0)	24.2 (6.8)	24.2 (6.7)
Gender [Man, Woman, Don’t answer (n)]	2020	117, 279, 4	117, 279	182, 212, 5	182, 212	116, 285, 1	116, 285	225, 248, 1a	225, 248	353, 157, 8	353, 157
	2021	161, 229, 2	161, 229	175, 217, 7	175, 217	104, 290, 5	104, 290	227, 165, 2	227, 165	88, 327, 6	88, 327
	2022	160, 227, 6	160, 227	115, 274, 9	115, 274	87, 306, 4	87, 306	201, 186, 7	201, 186	143, 280, 9	143, 280
Academic career [university degree or higher, less than a university degree (n)]	2020	199, 201	197, 199	246, 153	242, 152	230, 172	229, 172	294, 180a	293, 180	355, 163	351, 159
	2021	215, 177	215, 175	255, 144	251, 141	235, 164	231, 163	281, 113	279, 113	352, 69	347, 68
	2022	219, 174	216, 171	227, 171	225, 164	211, 186	208, 185	305, 89	298, 89	370, 62	363, 60
Children under junior high school age in the family [presence, absence (n)]	2020	124, 276	124, 272	97, 302	97, 297	113, 289	113, 288	112, 362a	112, 361	222, 296	220, 290
	2021	116, 276	116, 274	98, 301	96, 296	134, 265	134, 260	38, 356	38, 354	171, 250	168, 247
	2022	107, 286	107, 280	84, 314	83, 306	139, 258	139, 254	28, 366	28, 359	144, 288	143, 280
Elderly people over 65 in the family [presence, absence (n)]	2020	76, 324	73, 323	66, 333	66, 328	61, 341	61, 340	111, 363a	111, 362	190, 328	187, 323
	2021	110, 282	108, 282	61, 338	60, 332	57, 342	55, 339	79, 315	78, 314	145, 276	143, 272
	2022	117, 276	115, 272	73, 325	73, 316	60, 337	60, 333	83, 311	81, 306	111, 321	109, 314

Notes.

SD

standard deviation

n

number

^aTwo individuals had missing data.