How to compare a task's start variance to overall baseline project duration

Seems like this should be easy, so maybe I am missing something?

I need to compare an individual task's start variance (I know how to get this as I need it) to the project's OVERALL BASELINE duration.  I do not want to compare to the project's (current) Duration, and I do not want to compare to the individual task's duration - I need the overall project's basline Dur.

In other words, I have a Project Baseline Duration of ~77d and Duration of ~85 and I want to see how Task N's Start Var of 3d compares to the Project Baseline Duration.  In this example, I am looking for 3.90% from 3d/77d, not 3.53% which is 3d/85d.

When I started out, I thought this would be simple, but I am stumped.

Any help?

Thanks