I have had a surprisingly large response to my question, thank you. I found the comments were the most interesting part of it. The general consensus is that you can't come up with a number or ratio that applies to everyone. So I guess the best you can do is have a range of your own and depending on distance and elevation gain try to estimate how comfortable, or uncomfortable you will be. Having said that I did find the stats somewhat interesting. I threw out the guy who is so strong he has no problem carrying 50 pounds. It seemed too much like an anomaly.
The range was 20 to 40 pounds. The average was 26.55 lbs and the average ratio was 16.9% of body weight. That would put me at 29.5 lbs. I wouldn't mind starting a trip with that, including food and water, but I'd be happy when some of the food was gone. That figure also seems not to far off from some "experts" on line that suggested 25 lbs, 30 lbs (boy scouts) 27 (for 7 days) and someone who said 31 pounds was lighter than the majority of people they see backpacking out of Yosemite (a ranger?). So thanks for the info from all who answered. My conclusion? For me, between 14.9 and 16.9 percent of my body weight is a good range for my pack and food and fuel (not water) for a week. And, as a matter of fact, I usually start a week trip with 26 lbs, (includes fuel and food, not water).