All the time periods your data is calculated around, is based on the timing intervals you have set up for your report.
You can send reports on several intervals
Daily - data is calculated everyday on a daily basis
Weekly - data is calculated everyday on a weekly basis and accounts for 7 days worth of data
Monthly - data is calculated everyday on a monthly basis
Quarterly - data is calculated everyday on a quarterly basis
Functions
data reports can be paused so they do not send out
alternatively - timing is given for each report send out and when you can expect it in your inbox!