Test report: Test execution completion over time

I am looking at the report "test execution over time (aggregated per day)" for our daily regression run.

It shows the daily pass and fail status but there is a line on top which points to expected number of test cases by adding tests from the results of that day and the previous runs. This is strange as all tests required are executed everyday (around50-70) while the aggregate shows huge numbers making the report unreadable. Does anyone know how I can filter the aggregate?