In which was about eighty percent of the population engaged in the late 1700s?

1. nobility - in French: 'la noblesse' (less than 1% of the French population in 1789) 
2. clergy - in French: 'le clergé' (about 1% of the French population in 1789 - the vast majority such as poor priests, made up the low clergy) 
3. commoners (everybody else) - called in French: 'le Tiers Etat' - representing nearly 98% of the population. More than 90% of the French population were poor peasants or day laborers)

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The fact that farmers were paid for destroying crops.