More than several. Given how captives were treated, there was probably a need to make war on neighboring people just to maintain a living slave-labor workforce. Probably still a better deal than the one the Aztecs gave the losers in their "Flower Wars".
I noticed that the wiki-wacky page on Slavery in Ancient Egypt has a lot of disclaimers about, for example, how forced labor was different from slavery. ;^)
lot of disclaimers about, for example, how forced labor was different from slavery.
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Considering that most labor was carried out voluntarily by farmers, after their crops were harvested, in exchange for grain to feed their families.