I wonder how many of them were actually stolen in order to get access/entry to the US. Some pretty unsavory types might even have picked up families of convenience to do so (thinking Cartel types, etc.) Hard to say how many were employed as drug mules (without pay), too.
You left out how many were sold to adults coming in illegally as cover and then sold as slaves of one type or another to recoup what they paid and then some.
When adults are back in charge the border should be slammed shut for at least a decade because of all the illegals the democrat machine brought in.