Table 2.

Characteristics of PEMFC scientific article between 2008 and 2018.

Year	TP	NA	NA/TP	NR	NR/TP
2008	1053	4476	4.3	32006	30.4
2009	1128	5040	4.5	37924	33.6
2010	1354	6238	4.6	44515	32.9
2011	1411	6506	4.6	48895	34.7
2012	1383	6635	4.8	48558	35.1
2013	1286	6422	5	47548	37
2014	1431	6824	4.8	55508	38.8
2015	1460	6923	4.7	61082	41.8
2016	1480	7465	5	63218	42.7
2017	1532	7894	5.2	68988	45
2018	1502	7630	5.1	69299	46.1