Table 2
Events analysed by continent.
| Continent | Total | Period % | |||
| Events | % | 1964-1999 | 2000-2014 | 2015-2020 | |
| Europe | 102 | 37.0 | 44.2 | 45.2 | 30.4 |
| Asia | 64 | 23.2 | 22.2 | 14.0 | 39.2 |
| North America | 43 | 15.6 | 33.3 | 17.8 | 11.8 |
| South America | 29 | 10.5 | 0.0 | 5.7 | 16.7 |
| Oceania | 19 | 6.9 | 0.0 | 10.2 | 2.0 |
| Africa | 11 | 4.0 | 0.0 | 7.2 | 0.0 |
| Various | 8 | 2.9 | 0.0 | 0.0 | 0.0 |
| Total | 224 | 100 | 100 | 100 | 100 |
