Table 6.

Country scientific production

Rank	Country	Frequency
1	USA	1047
2	China	804
3	India	382
4	Italy	360
5	United Kingdom	262
6	Canada	152
7	Spain	127
8	South Korea	126
9	Germany	117
10	Australia	96
11	France	80
12	Saudi Arabia	80
13	Singapore	74
14	Turkey	72
15	Iran	71
16	Egypt	65
17	Pakistan	60
18	Brazil	59
19	Netherlands	49
20	Vietnam	43