From Perceptions of Probability and Numbers. This is a useful reference point. People will often use verbal descriptions in place of specific numeric estimates. Sometimes this is intentional in order to maintain some wiggle room, as when making a forecast. Often, I suspect, it is simply unconscious. Regardless, verbal generalities are no substitute for real numbers if they are available.
So what do we mean when we say something is "likely to happen?" Is "likely to happen" 20%, 40%, 60%? More than 80%? There are some reference guides here and there which are useful, but what do these terms mean in the vernacular when used by the public? From this research, we know that an average person using the phrase "likely to happen" means, on average, that there is a 70% probability of it happening and with a range of 65-75% probability.
Here is the full list.