When testing I noticed that after exporting graph as CSV file its data becomes incorrect.
As administrator navigate to Reports > View Reports > Orders.
Count the number of 'Did not report', 'On time' and 'Unscheduled' occurances in Reporting Rate And Timeliness.
In All-Time Reporting Timeliness section click on the three dots and choose Export CSV.
Open the file and check that the values are different than counted.
The values in CSV file are correct.