Table 6.

Most prolific countries and the collaborations

Region	Rank	Countries	Total papers	%	Total citations	Citations per paper	Intra- country collaboration	%	Inter-country collaboration	%	Distinct countries of collaboration	Main collaborator (and number of collaborations)
North America	1	United States	8232	60.2	252,935	30.7	6403	77.8	1829	22.2	96	England (244)
	3	Canada	701	5.1	18,020	25.7	362	51.6	339	48.4	63	USA (216)
East Asia And Pacific	4	Australia	682	5	16,143	23.7	300	44.0	382	56.0	63	Wales (152)
	9	China	338	2.5	6720	19.9	94	27.8	244	72.2	55	USA (142)
	20	Japan	129	0.9	1991	15.4	87	67.4	42	32.6	47	USA (17)
	24	Taiwan	107	0.8	1597	14.9	65	60.7	42	39.3	26	USA (22)
	27	South Korea	100	0.7	1587	15.9	54	54	46	46	23	USA (31)
	28	New Zealand	99	0.7	2250	22.7	53	53.5	46	46.5	16	England (19)
	33	Hong Kong	68	0.5	1088	16	1	1.5	67	98.5	43	China (67)
	34	Malaysia	66	0.5	1005	15.2	17	25.8	49	74.2	42	USA (31)
	39	Singapore	42	0.3	1553	37	16	38.1	26	61.9	30	USA (10)
Europe and Central Asia	2	England	1064	7.8	37,226	35	510	47.9	554	52.1	71	USA (244)
	5	Italy	379	2.8	9989	26.4	190	50.1	189	49.9	54	USA (82)
	6	Netherlands	379	2.8	9771	25.8	185	48.8	194	51.2	53	USA (85)
	7	France	372	2.7	8250	22.2	150	40.3	222	59.7	49	USA (109)
	8	Germany	341	2.5	8503	24.9	148	43.4	193	56.6	46	USA (76)
	10	Spain	315	2.3	6734	21.4	178	56.5	137	43.5	66	USA (53)
	11	Switzerland	240	1.8	6077	25.3	70	29.2	170	70.8	52	USA (96)
	12	Sweden	232	1.7	7483	32.3	116	50	116	50	38	USA (37)
	14	Wales	197	1.4	6742	34.2	12	6.1	185	93.9	40	Australia (152)
	18	Norway	144	1.1	3992	27.7	67	46.5	77	53.5	31	USA (26)
	19	Denmark	132	1	4716	35.7	80	60.6	52	39.4	27	USA (19)
	21	Georgia	129	0.9	3044	23.6	3	2.3	126	97.7	16	USA (120)
	25	Scotland	101	0.7	3135	31	31	30.7	70	69.3	35	England (47)
	26	Finland	100	0.7	1981	19.8	47	47	53	53	28	Sweden (17)
	29	Belgium	96	0.7	2798	29.2	35	36.5	61	63.5	40	Netherlands (28)
	30	Turkey	93	0.7	967	10.4	79	84.9	14	15.1	24	Germany (3)
	31	Austria	78	0.6	1974	25.3	43	55.1	35	44.9	24	USA (19)
	32	Ireland	75	0.5	1373	18.3	52	69.3	23	30.7	33	England (10)
	35	Poland	63	0.5	1263	20.1	44	69.8	19	30.2	45	USA (10)
	38	Greece	42	0.3	1312	31.2	21	50	21	50	34	England (9)
	40	Portugal	39	0.3	1018	26.1	11	28.2	28	71.8	42	Italy (10)
Latin America and The Caribbean	17	Mexico	178	1.3	6888	38.7	16	9	162	91	43	USA (156)
	22	Brazil	127	0.9	2363	18.6	62	48.8	65	51.2	53	USA (30)
Middle East and North Africa	13	Israel	200	1.5	7132	35.7	65	32.5	135	67.5	46	USA (126)
	16	Iran	188	1.4	1396	7.4	98	52.1	90	47.9	39	USA (39)
	23	Oman	115	0.8	1901	16.5	1	0.9	114	99.1	48	USA (62)
	36	Lebanon	53	0.4	2713	51.2	1	1.9	52	98.1	34	USA (50)
	41	Jordan	34	0.2	252	7.4	4	11.8	30	88.2	11	USA (26)
South Asia	15	India	195	1.4	3887	19.9	71	36.4	124	63.6	43	USA (109)
Sub-Saharan Africa	37	South Africa	53	0.4	1166	22	25	47.2	28	52.8	27	USA (14)