I used to average 12.5 mph for my trips, back when my cyclecomputer worked.
Since it stopped, I suspect to battery failure, I can only tell my cadence and soon I'll remove that. I used to track all my miles and my times, which was fun for awhile, but I never did anything with it and I hit a plateau that I couldn't get over. Now I prefer the simple life of riding just to get to work or home.
I always wanted but never followed through on plans to complete the tracking of times by counting calories, measuring heart rate peaks, and keeping track of my record rides, which I tracked for awhile but it was so tied to the wind that I couldn't really tell what was my best rides.
In the end, I thought that if I didn't correspondingly track my calorie intake by measuring my serving sizes of food, then it didn't come full circle. Maybe one day I will do this.
Better parameters for my rides now are my number of trips/week, the burning in my thighs, and a consistent effort on the hills. If so, I'm doing well.
The other thing I want to add is that this is personal. You can't compare your situation with another unless you get a heck of a lot of detail. I've got a "comfort bike" that I burden down pretty good with gear--that's different than a road, cross, or mountain bike. I vary my routes and if I'm on the road more, I'm faster than I am on the MUP. Due to issues like these, I don't think you can learn a lot from speed data.