National Public Radio reports: "It's typical for young gays, who have often fled hostile environments, to make up a large proportion of the homeless who are under 25 — perhaps as much as 40 percent in major cities such as Boston and Los Angeles."
That "perhaps" is an alarm bell. Perhaps it's as much as 75 percent. Perhaps not. There's no link to any survey to back up the NPR claim. Google turns up a 2007 report by the National Gay and Lesbian Task Force, an advocacy group, that found, "Of the estimated 1.6 million homeless American youth, between 20 and 40 percent identify as lesbian, gay, bisexual or transgender." So NPR takes the advocacy group's estimate of "between 20 and 40 percent" and, without attributing the source, ramps that up to "a large proportion...perhaps as much as 40 percent."