SFTP (OpenSSH) Bandwidth Accounting

New to Unix Networking. I was wondering if there is a way to monitor
updload/download bandwidth used with the openSSH server per linux
user. Tried UserIPaccnt but it was meant for 2.4 kernel and couldnt
get it to work. Someone suggested using Iptables but I have no idea
how to do this because I can't figure out how to see the destination
user id for incoming data.

Any help or suggestions would greatly be appreciated.
--Sachin