Thematic research clusters in very old populations (≥ 80 years): a bibliometric approach

BMC Geriatrics

Table 2 Top 30 most productive countries for research output related to people aged 80 and over

Country	2000–2004		2005–2009		2010–2014		2015–2019		TOTAL
Country	N	%	N	%	N	%	N	%	N	%	N publications per million inhabitants
USA	6	40	1627	32.	2233	27	2177	25.4	6043	27.7	18.4
Japan	2	13.3	594	11.9	1011	12.2	1471	17.2	3078	14.1	24.4
UK	2	13.3	526	10.5	647	7.8	558	6.5	1733	7.9	25.9
Italy	–	–	361	7.2	605	7.3	630	7.4	1596	7.3	26.5
Germany	–	–	239	4.8	524	6.3	563	6.6	1326	6.1	15.9
France	–	–	225	4.5	555	6.7	527	6.2	1307	6	19.5
Spain	1	6.7	193	3.9	508	6.1	587	6.9	1289	5.9	27.4
Australia	1	6.7	185	3.7	314	3.8	360	4.2	860	3.9	33.9
Canada	1	6.7	175	3.5	303	3.7	328	3.8	807	3.7	21.5
China	–	–	82	1.6	247	3	453	5.3	782	3.6	0.6
Netherlands	–	–	145	2.9	243	2.9	216	2.5	604	2.8	34.8
Switzerland	–	–	93	1.9	170	2.1	180	2.1	443	2	79.5
Sweden	–	–	97	1.9	160	1.9	184	2.1	441	2	42.9
Taiwan	1	6.7	115	2.3	164	2	161	1.9	441	2	19.1
Belgium	–	–	75	1.5	163	2	127	1.5	365	1.7	31.8
Turkey	1	6.7	78	1.6	154	1.9	131	1.5	364	1.7	4.4
South Korea	–	–	47	0.9	127	1.5	174	2	348	1.6	6.7
Greece	–	–	109	2.2	119	1.4	92	1.9	320	1.5	29.9
Israel	–	–	69	1.4	98	1.2	125	1.5	292	1.3	32.2
Brazil	–	–	37	0.7	125	1.5	130	1.5	292	1.3	1.4
Austria	–	–	51	1	79	1	92	1.1	222	1	25.0
Finland	–	–	36	0.7	83	1	88	1.	207	0.9	37.5
Portugal	–	–	17	0.3	59	0.7	110	1.3	186	0.8	18.11
Denmark	–	–	44	0.9	59	0.7	76	0.9	179	0.8	30.8
Singapore	–	–	26	0.5	53	0.6	83	1	162	0.7	28.4
Poland	–	–	15	0.3	60	0.7	65	0.8	140	0.6	3.7
Norway	–	–	25	0.5	52	0.6	62	0.7	139	0.6	26.0
New Zealand	–	–	21	0.4	60	0.7	57	0.7	138	0.6	28.1
Ireland	1	6.7	32	0.6	44	0.5	45	0.5	122	0.6	24.7
India	–	–	27	0.5	46	0.6	45	0.5	118	0.5	0.1

ISSN: 1471-2318