Headcount by week or date returning blanks

Summary:

Is there a way to report a headcount trend by week or by date using Workforce Trend subject area?

Content:

I'm trying to build a report that shows headcount by week or by date for the last few months using Workforce Trend Real Time. The report works if use months instead of weeks but any increments smaller than months returns blank rows for every date. Is there something I'm missing or is it not possible to build this kind of trend report?