How to baseline large network

Baseline, baseline, baseline is what I keep reading but I'm not finding any good tutorials on how to do so. I take captures from our core network but I have to split them off into 100MB file sizes because there is so much traffic coming through them. I can then go into each file and view statistics but that is cumbersome and doesn't give me one report to view overall network traffic and port usage. You can't export the protocol hierarchy statistics, so how am I supposed to create a baseline?

Anyone have luck creating a baseline report on a large network? I'd like to take captures of the core network once a month and create reports/statistics on top talkers and protocols in use.