According to one estimate, between 15 and 17 percent of all households in the United States could benefit financially from filing bankruptcy. Only about one-tenth of them do so. I learned this from The Two-Income Trap (reviewed by me immediately below). The book draws on the research of Michelle J. White, here is her on-line summary of her work. This also suggests that current bankruptcy law is unsustainable in the long run, here is one of many calls for reform.