The share of people in the labor force involved in agricultural work has not only declined, it has declined dramatically over the last century. Although agricultural employment had already been in gradual decline from its peak, the widespread introduction of the mechanized tractor and combine in the 1920s caused a sharp decline which has continued, though at a slower pace, to this day. Currently about 2% of the workforce is engaged in agricultural production, down from 50% a century and a half ago.