How have the labor trends shifted in the last 50, 100 years? Labor intensive jobs(also calorie intensive) are down. Even the jobs that remain have more of the

How have the labor trends shifted in the last 50, 100 years? Labor intensive jobs(also calorie intensive) are down. Even the jobs that remain have more of the physical demands taken out i.e. using an airgun to frame up a house instead of a hammer.