Given the task definition and input, reply with output. In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

Article: Generational differences and the economy are shifting more responsibilities for children from their parents to grandparents, according to a new survey. More than one-third of grandparents aged 50 and older contribute financially to their grandchildren's upbringing, and 11 percent have a grandchild living with them, the poll by AARP showed. 40 percent of people who responded to the telephone survey, whose average age was 69, reported spending more than $500 on grandchildren over the past year beyond traditional gifts. Education costs accounted for about 50 percent, daily expenses for about 32 percent and medical and dental costs for about 18 percent.16 percent provided daycare for grandchildren. "They are the safety nets for American families, helping to pay for practical expenses and necessities,"said Amy Goyer, AARP's multigenerational and family issues expert. "We see many providing daycare services, while growing numbers even have grandchildren living with them,"she said, referring to the 16 percent who watch their grandchildren while the parents are at work or at school. Overall, nearly 90 percent of the 1,904 grandparents questioned said they play a very or somewhat important role in their grandchildren's lives, and about 70 percent live within 50 miles of the closest one. The poll conducted by Woelfel Research Inc. also showed that grandparents increasingly adapted to the younger generation's life issues and preferred ways of communicating. More than one-third connect with their grandchildren via email, Skype or text messaging, while half said they routinely discuss topics ranging from values to drug and alcohol use. Nearly 40 percent said they had discussed dating or sex with at least one grandchild. About 60 percent said they spoke with their grandchildren at least once a week. Most of the grandparents said they had five or more grandchildren, while one-fourth said they have grandchildren of a different race, mixed race or different ethnicity.
Answer: When there are three generations in the family.
When do the 16% of the grandparents polled take care of their grandchildren?