New or return customers? If new customers, how did they hear about you? Referral? You'll likely have several different figures depending upon how they got your info.
New customers who just found me online I'm about 40%, but that's only because I try and pre-qualify them before ever considering a site visit. I get a description from them over the phone or email, then I'll provide a brief explanation of the service I'm proposing as well as a price range. I let them know if the price range sounds reasonable to them, then we could meet to discuss & finalize the details.
New customers who were referred to me from someone I've serviced in the past would be about 65%.
Return customers about 90-95%
When I first started my own biz in 1998, I thought I was killing it because I got most of the jobs I went and bid on. Come to find out it was only because I was offering my services way too cheap, (that's typically because many of us don't truly understand our total operating costs when starting a business).
Although situations vary, I'd say that if you're closing % is much more than 50% from people who don't know you and just found your info online or in print, then you need to reevaluate your pricing.