| Rank | Author | Number of Isotopes | Percent |
| 1 | USA | 1316 | 41.36% |
| 2 | Germany | 555 | 17.41% |
| 3 | UK | 300 | 9.43% |
| 4 | USSR/Russia | 245 | 7.70% |
| 5 | France | 214 | 6.73% |
| 6 | Switzerland | 129 | 4.05% |
| 7 | Japan | 126 | 3.96% |
| 8 | Sweden | 62 | 1.95% |
| 9 | Canada | 61 | 1.92% |
| 10 | Finland | 37 | 1.16% |
| 11 | Netherlands | 36 | 1.13% |
| 12 | China | 26 | 0.82% |
| 13 | Belgium | 17 | 0.53% |
| 14 | Denmark | 14 | 0.44% |
| 15 | Argentina | 12 | 0.38% |
| 16 | Italy | 11 | 0.35% |
| 17 | Austria | 6 | 0.19% |
| Israel | 6 | 0.19% | |
| 19 | Norway | 2 | 0.06% |
| Australia | 2 | 0.06% | |
| India | 2 | 0.06% | |
| 22 | New Zealand | 1 | 0.03% |
| Poland | 1 | 0.03% | |
| Brazil | 1 | 0.03% | |
| Hungary | 1 | 0.03% |