[lowpro]

Only the 98% of web traffic that goes through the US.

Although really the other 2% wouldn't be hard to get considering the power they have.

[cyphar]

NSA has partnership with many other nation states. They get much more data than just the data which goes through the US.

[Forbo]

For anyone wanting more information on this, it is commonly referred to as "Five Eyes": https://en.wikipedia.org/wiki/Five_Eyes

Also of note is the "Future Enlargement" section of that article, where it expands on other partnerships: "Six Eyes", "Nine Eyes", "Fourteen Eyes".