You will need to take checkpoint samples periodically so that you can forecast. Information that is over 12 months will not be reflective of the current traffic profile. Recommend that you start to take some snap-shot profiles a few times a week so that you can build up a traffic picture. This will help you with your forecasting and will allow you to dimension your IVR / VXML-IVR equipment and the connections that you will need.
You should also be aware of planned campaigns or new Services that will be launched by your CSP. This will help you to plan for traffic “spikes”.