Depends on what you mean by average, I guess. On average, college graduates earn more than those who only hold a high school diploma. Exactly how much more depends on whose estimates you view. I think this is a good read that fairly summarizes both sides of the argument.
That link also demonstrates why gross income is only one variable in the equation. It also shows that that one variable is dependent on other variables—specifically the major. Seems to me that there is a possibility that a handful of outlier majors could be bringing the average income up. Which is why you also need to look at the median case, as well as the mode. Only then can you even begin to get an idea of what is actually typical.
In any case, I certainly don’t hold with measuring the worth of anything solely by its financial value.
Er, I was using the link to recognize that both sides have a valid argument -- that while there are some instances where college isn't worth it, there are plenty of other instances where it most certainly is (going beyond financial value). Overall, it is dependent upon the individual's choices, goals, and capabilities (financially, mentally, and otherwise).
I don’t deny that the answer to, “Is college worth it” is context sensitive. It just seems to me that that the context where the answer is “Yes” is getting distressingly narrow.
A lot of that is rising tuition costs and unfair laws about student loans, coupled with slashed state education budgets, which affect universities as much as they do K-12 schools.
A college education is a wonderful thing, and everyone should have the chance to at least
try for a degree. However, for this to happen, there need to be low-cost options. 2-year community colleges used to be a wonderful option, but since they, too, rely on state education budgets, they're just as susceptible to skyrocketing tuition.