Basically you need a process to bucket your data to the time period you want to report on. Depending on what your time measurements represent the CPU data would go in the same bucket. For example time 1 and 2 might go in bucket one, times 3 and 4 in bucket 2 etc.
We do something similar with survey data. Responses may come in over the course of many days or even weeks. To report trend data we roll up the data into day, week or month time periods.