When people reported it

The record runs from the 1940s to now. This is how it is spread, and what that spread does and does not tell you.

Everything, by decade

What these numbers are not

They are not a measurement of how often strange things happen. They measure how often people wrote them down, which depends on whether a place to report existed, whether anybody had heard of it, whether the subject was in the news that year, and whether the archive was still being maintained. The internet arriving is visible in this chart, and it is not evidence of anything except the internet arriving.

Read the shape rather than the height: a characteristic that rises while everything around it falls is worth a second look. A characteristic that rises in step with the total is probably just following the crowd.

By what people described