Home and rent prices in the United States have increased 73 percent and 61 percent, respectively, since 2000. But incomes for millennials haven't matched that: They've increased only 31 percent in the same time frame.

Apartment List conducted a survey of more than 13,000 millennials to determine how many receive regular help from family with rent or a down payment, as well as how much assistance they receive. According to the findings, about 8 percent of non-student millennials receive money from family members in order to pay rent each month, and "while most of these renters receive relatively small sums each month, one in three receive rent in full from their parents."

Another 15 percent still live with their parents to cut costs. And, since not everyone can get or will take support, one in four millennials ends up spending more than half their income on rent.

Apartment List points out that assistance comes in different forms, too, since "40 percent of millennials receive help from parents with everyday expenses, including rent, child care, phone bills and car payments. An even larger share likely receive one-time help, such as help with a down payment, moving costs or money after losing a job."