3 to 1 sounds about right for initial responses, assuming you pick jobs that you are obviously qualified for. this goes up and down, obviously, depending on how qualified you appear to be for the position you are responding to.
Once you get the initial response, there's still a pretty good chance of the gig falling through for whatever reason. Contracting is rough this way, really no matter where you get your clients.
I've only recently started hunting for gigs via CL. I've picked 3 and responded (I took time to write what I thought was a good, carefully-worded response) within 24 hours or so but no one's responded back. I know sales is all about volume, I'm just trying to get an idea of what to expect.