The headline on the story is the half of American adults live within 18 miles of their parents.
In the college-educated class - roughly a quarter of the population - the distances typically get much greater, as the Gruntleds can attest.
Hidden in the report is this interesting additional fact:
labor force participation by married women with children increased by as much as 10 percentage points when they lived near their mothers or mothers-in-law
Professional men and women tend to go where the job is, regardless of family ties. However, professional women, if they have any choice in the matter, tend to try to live near their mothers. The help that grandparents give is especially important for emergencies, more than for daily care.
This is a good idea to bear in mind when professional and managerial couples are starting out: plan to live near backup care before you have kids, if at all possible.