Generally Speaking if things are relatively straightforward and the Parties generally agree I have had Mediations finish up about 80% of the time with the results below. Of course some parties prefer to take things slower, or some parties have complicated situations that require more consideration, and those mediations may take longer. Lots of factors affect the final timeframes of course, but these have been typical over the past decade.
While individual cases and situations can cause mediation times to vary, here is list of average mediation times based on the past 17 years.