salary for employees of consultants

What percentage of the billing rate do employees of consultants usually get? I am employed by a guy running a sole-ownership consulting co. It’s just me, him and one other employee. I think I’m not getting paid enough but I don’t know how to tell. Iam a CNA, MCP and A+ with 4 years IT experience, 1 year consulting, and live in the SF bay area. Any comments?