Just about every economic historian who has looked at the issue believes that standard measures of productivity have consistently understated the true improvement in living standards for at least the past 140 years.
Economic historians study how productivity affects our standard of living.
Historians say our standard of living is getting steadily worse.
a group of people are ina  room
He had such a smile on his face.
two people running a marathon
The invaders pushed deeper into Byzantine territory, causing troubles for the empire.
I'm not afraid of you at all.
A woman is lying down with her pet.