I mean, in industrialized countries, where working construction might mean your job is actually to operate a bulldozer or a back-hoe. How many people, nowadays, get enough physical exercise in the course of a day’s work?
You have obviously never worked in construction. 
Operating engineers (the guys running equipment) make up a very small portion of the total workforce on a construction job.
When I was fresh out of high school, I worked on a major hospital job. Total crew was probably 100 guys between laborers, carpenters, plumbers, electricians, A/C, various other subs, and what not. We had two operators for the tower crane.
There are plenty of physical jobs out there.
Warehouse pickers spring to mind. They are the ones that go around warehouses pulling boxes from racks to fulfill orders. Migrant farm laborers have both the glamour and the physical aspect in their job. Farm hands and cowboys get lots of exercise. Then there is aerobics instructors.
Mailmen. (People/persons.)
Around here they still go on foot through the neighborhood on a route that can be many blocks as they still have to go door to door, and the doors are generally 50 feet apart or less. And we’re not so densely populated with apartment buildings in this part of the city, it’s still mostly single family houses.
Bakers, lots of sheet pan lifting. Also if you’re in the oven room it’s like a sauna in some places (without the moisture.) Of course it really depends on where you work.
People that work in the kitchen of busy restaurants get a lot exercise. It is surprisingly physical and the pace gets to be very fast.
Dishwashers. I am constantly running from one end of the dishwashing area to the other…about 20 feet in length…do that probably 200 times a day. Then i have to take dishes up front, so im walking with 70-80 pounds of dishes in my hands. Plus the rush of everything, its pretty exhausting. I would say i get a good workout at my job. (And im 16 by the way, lol, so you guys dont think im some loser working at a minimum wage dishwashing job)
Probably if you break things down by salary and figure out what the highest paying non-desk job is, you can do a linear drop off where you assume that 90% of minimum wage jobs are physically active and 0% for anything over the max physical labor job’s wage.
Obviously that would just be a guesstimate, but it should be ballpark to within 15-20% or so, I would guess.
Then again, some high level positions might require enough time running around airports and whatnot that you can’t necessarily assign them to being desk jobs. There are some jobs where you’re on the road five or six days a week.
I used to be a restaurant cook and have nothing but respect for the dishwashers. When the rush is on, you guys keep the kitchen moving. Peace.
As for physical jobs, you’ve reminded me of delivery people in general. Bike couriers, food and beer delivery, furniture delivery…those guys (and girls) have it tough. And, to use one of my favorite obscure words, don’t forget stevedores!
Not so much in IT, or at least my current IT position.
When I worked in hospitals, I certainly got plenty of walking. Often I’d move from one end of the campus to the other multiple times per day, depending upon how I recieved the work requests… then there were the stairs… in some hospitals it was easier to go up 2 flights of stairs, and down any number of flights, than it was to take the very slow, very crowded elevators.