Openfire JWchat loading bandwidth

I have website having JWchat as client & openfire as XMPP server. Jwchat is made for autoinvocation when someone visits the website. It is taking almost huge data bandwidth. Everyday for one website for user of 10 -15, I am getting 5 GB datatransfer which is quite huge. Please can you help me on this. Please can you help me on this.