How to improve Registration Conversion

Dear all,

I am now running a short year again with Telligent and I see some stats that raises my question. What is a benchmark conversion rate between people that

  1. Click on the JOIN button and
  2. People who finally come in

I looked at 

  1. The Google Analytics for Unique Visitors  in a month with the root+/user/createuser (blue)
  2. The Telligent User dump of that same month (green)
  3. The Conversion rate (orange)

See my graph. As you can see we are in startup but anybody know the conversion benchmark. I'm losing north of 60% of my registrations during the process. How to improve this?