Add a (constant) line in a chart inside a report

Hi,

I am creating a report with a chart. The data comes from a a PDI transformation. I have been asked to add 2 lines to the graphs. Let's imagine in a chart with Y scale from 0 to 100 I have to add 2 lines with value always 80 (maximum recommended value) and the second one with value 20 (minimum recommended value).

I can add two tuples date/value with value equal to 80 and 20 at PDI level and show them on the report. But for simplicity shake I would like to add this constants values at the report level.

Any idea how to achieve this?

Thanks for your time

Best regards