95 years after publication. Many other countries also have an X years after the author's death clause where X varies between countries but is at least 70.

There are also other weird issues such as the UK having a clause protecting Peter Pan (so a children's hospital gets royalties) and the King James translation of the bible (under Crown copyright) that extend the copyright even further.

In short, it's a mess.

The thing I find most hypocritical though is that they are probably never share their libraries with anyone. After scanning, downloading, stealing, overloading websites and everything in between, to acquire enough data for their stupid machine, they're not going to share their data? I get that most of it can't be shared, but a lot can. There's no reason why you need to destroy multiple copies of a book from 1880, when it's free to share.

At the same time I can understand keeping track of when each books enters public domain might also be an absolute nightmare, and I wouldn't blame the AI companies for not wanting to deal with that. For the stuff they absolutely know is clear, they should provide dumps for everyone to download.