I went to the marathon results, sorted them by my age group, and then did the calculation.

It works like this: Say I was #85 out of 110 in my age group. That would mean I finished ahead of 25 (110-85) of my 109 competitors (110 minus me). So I beat 25/109 of them. Dividing 25 by 109 comes out to about 22.9%.

(Pardon me if that calculation is obvious to you — I worked for many years as a math teacher, so I can’t help explaining things like this.)

I do the same as you — try to maintain a consistent effort. This means that on uphills, I slightly reduce my cadence and significantly reduce my stride length (more so on steep hills). This approach works well for me; without it, I’d tire myself out too much on uphills.

On downhills, I try to glide down, lengthening my stride a bit but not speeding up too much. (In my early running days, I pounded too hard down some hills during a race, tore my medial meniscus, had surgery, and missed years of running.)

As you’ve noticed, many runners don’t follow the even-effort strategy. Maybe that’s because different approaches work well for different people (and yes, your weight gives you more of a reason than most runners to slow on the uphills). But another reason may be that runners in your pace group don’t tend to be highly educated about running strategies. (Just taking a guess here.)

P.S. If you’re 52 and 5’9” and 220, and you’re running a half marathon in just over 2:00, you’re doing a fantastic job!