To name something else:
It irks me quite a lot that people think (and say) that 'nobody came back from Russia', and that those who didn't come back died. Same goes with the 'all-murdering cossacks'.
Fact is, I've come by hundreds of Dutch Russia-veterans who joined up in the new Dutch army in 1814. While undoubtedly a good deal of them died, many more had come back, were still imprisoned or on their way back from Russian imprisonment. Many of these POW had been captured by cossacks who usually robed them, and passed them over to the prison camps.
So yes, a majority of the men never returned, but certainly not all.
I wish I could give a good estimation, but it really differs per battalion. One Russia veteran in every fifty soldiers is a good guess, and it's certainly not below that.