Haciendas of central Chile are believed to had become labour-saturated by 1780 generating an "excess" population that could not be incorporated into their economy. Some of this population settled in the outskirts of larger cities while other migrated to the mining districts of Norte Chico. Chile saw an unprecedented revival of its mining activity in the 18th century with annual gold production rising from 400 to 1000 kg over the course of the century and the silver annual production rising from 1000 to 5000 kg in the same interval.