2000 Trooper 3.5L V6 Compression

What is the acceptable range for piston compression on a 2000 Isuzu Trooper with a 3.5L V6 engine (4WD)? I'm thinking that if the oil consumption is due to wearing rings, I should have experienced a drop in compression. I cannot detect any loss of performance in the engine and the mielage is about 19 MPG highway - about average for a mid-size SUV with the aerodynamics of a billboard sign.