What is the lookback period of the 'date through' option of the Optimal Frequency report?

• Audience Manager
• Tableau reports
• Optimal Frequency report

In the Optimal Frequency report, if I were to select my “date through” as today, would that take into account the last 30 days, the last week, the last 90 days, or some other period of time?

For the Optimal Frequency report, the report is a 30-day fixed look-back time period.