http://www.janis7hepc.com/Modes%20of%20Transmission.htmThis says in a mongamous relationship for hetersexual monogamous partners it is up to 3% chance of transmission in 20 years.
Please understand this is the transmission rate, but there is probably no good method of differentiating whether it was transmistted some other method; sharing a toothbrush or razor, and many other vectors.
I'll see if I can also drop a link to a useful thread here.
Here is a decent read.... please note there are 3 pages of thread.
http://www.hcvanonymous.com/SMF/index.php?topic=1558.0best,
Willy