When Contractors Ask What Other Bids Were

[Account Closed]

I'm new to the rehabbing world and am trying to learn the best ways to communicate and work with contractors. 

I recently contacted several concrete companies to submit bids for replacing a 10x60 sidewalk. One of them gave me a bid over the phone after I described the job, then immediately asked what the other guys bid or the work. 

Is that pretty standard? Any recommendations for the best way to handle questions like that? I didn't know if it was appropriate to tell him or not, so I said they were competitive.

Thanks!