Of the 600 detainees who have left Guantanamo Bay, just under 16% of them have re-engaged in terrorist activities—and the director of National Intelligence yesterday pointed out that's a smaller figure than the 27% a Republican congressional report cited last month. That's because the earlier report combined the confirmed figure with a suspected one: Another 12% are believed to have rejoined a terror group. The AP notes that this is the first time the numbers have been broken down so specifically.
As for that 12%, the report says that they're essentially on a watch list, meaning their behavior and associates are continually being tracked, though no further details on the specifics of the monitoring were released. One more detail from the report: In an apparent nod at Yemen, it warns that detainees released to unstable countries are more likely to rejoin a terror group.