All of these times are for visitor visas, and I just pulled them from the State Department's web site. As you can see, it varies significantly depending on where you live.
Toronto: 42 work days for appointment + 2 work days for processing
Montreal: 42 work days for appointment + 4 work days for processing
Vancouver: 22 work days for appointment + 2 work days for processing
Calgary: 3 work days for appointment + 2 work days for processing
Ottawa: 14 work days for appointment + 2 work days for processing
Quebec City: 10 work days for appointment + 1 work day for processing
Halifax: 10 work days for appointment + 4 work days for processing