Measuring Network Bandwidth Utilization

[robertlaferla at attbi.com (Robert La Ferla)]

Network Gurus,

I'd like to measure how much network bandwidth my Linux 2.4 system is
using.  What's the best way to do this?  Say, I have a 10Mbps
connection, I'd like to determine what percent of it is being used on
average over different periods of time (hourly, daily, weekly,
monthly.)  I looked at "iostat" and "netstat" but that's a bit too
low-level and doesn't really give me what I want.

Thanks,
Robert