The economy may be improving but many American families are still weighed down by debt and without a safety net.

Piggy bank

One out of five families owes more on credit cards, medical bills, student loans and other unsecured debt than they have in savings, according to a new University of Michigan report. And the number of families surveyed at the end of 2011 that have no savings at all increased to 23.4 percent, compared with 18.5 percent in 2009.