Below is a graph of my average pace at my MAF since I first starting using MAF on 8/4/08 as a way to control my training efforts during this base building stage.
My pace on 8/4/08, 9:14/mile, AHR 145. My pace on todays run, 7:52/mile, AHR 147. That's a 15% improvement of pace/m in a little over a month using the same HR/effort. The outlier on the 29th day was a run done without a HR monitor. I just ran a nice and easy relaxed pace to where I felt good, the average pace for that run was 7:30/mile. If I had worn my HR monitor, it felt like it could probably be around 160.