Note that your source does not argue the point you make directly after it. The graph explicitly covers only "non-agricultural activities". As for non-agricultur

Note that your source does not argue the point you make directly after it. The graph explicitly covers only "non-agricultural activities". As for non-agricultural activities, 1870 marks the early peak of industrialization before unions and worker parties forced schedules down to the now-established 40-hour-per-week mark. Unfortunately, the primary source for the graph (https://ourworldindata.org/working-hours https://ourworldindata.org/working-hours) does not say anything about agricultural working hours pre-industrialization. They note efficiency increases in agriculture through automation, but since the agricultural workforce declined at the same time, there is no clear answer at least from this source.