[arethuza]

As a one time practitioner of "good old-fashioned" AI I had thought it was ETAOIN SHRDLU

https://en.wikipedia.org/wiki/Etaoin_shrdlu

https://en.wikipedia.org/wiki/SHRDLU

[StavrosK]

That's close enough, and it'll vary based on the dataset. In the provided link, it's ETAOIN SHRDLCU, which is almost the same.