How do you track and report an Agile project %complete (as the project in whole) compared to % of budget spent within project time constraints?

[ChuckCa]

Basically I am being asked to provide a waterfall report in projects running in agile. The ask is to provide a report and dashboard that compares the percent of a project complete vs the percent of current cost against budget. As you know in Agile the individual tasks are not created until Sprint Planning and one user story could be 1 task or 20 which obviously would drastically change Project % complete.

I know I am not the first to come across this issue, what are you doing to satisfy those needs?