The 10,000 - total casualties?

[Timotheus]

Does anyone have a good source on the total losses of the 10,000 mercenaries under Xenophon as they retreated to the Black Sea? I have one source that says 5 out of 6 Greeks made it back and that a majority of the ones that did fall died of exposure climbing the mountains and not from battle. This sounds way too high, unfortunately while I can find dozens of places where I can read the entire journey I cannot find a decent summary with figures. I just do not have time at the moment to read the book.

Any help would be appreciated.