Mark 5

 When Jesus asked the name of the evil spirit in the possessed man, the response was - 

"...My name is Legion: for we are many."  (Mark 5:9)

Then the evil spirit requested that Jesus - 

"...would not send them away out of the country.

11 Now there was there nigh unto the mountains a great herd of swine feeding.

12 And all the devils besought him, saying, Send us into the swine, that we may enter into them.

13 And forthwith Jesus gave them leave. And the unclean spirits went out, and entered into the swine: and the herd ran violently down a steep place into the sea, (they were about two thousand;) and were choked in the sea."  (Mark 5:10–13)

In my mind, Legion must have been at least two thousand evil spirits.  Isn't it interesting that even then the evil spirits lost possession with the death of the swine.

Another thought is the owners of the swine mut have been non-Jews or unfaithful-Jews being that they are raising swine.