A record 49.9 million US adults went without health insurance for at least part of the past year, up from 46 million in 2008, according to a new report from the Centers for Disease Control and Prevention (CDC).

The uninsured now constitute 26.2 percent of the total adult population, more than one in four, up from 24.5 percent two years ago. Sixteen percent of adults, about 30.4 million, had been without insurance for more than one year at the beginning of 2010, an increase of 1.3 million in one year and also a record. In all, nearly 60 million Americans, about 20 percent of the population, went without insurance.

The sharpest increase in the uninsured took place among adults in middle class households. Nearly one third of adults in households that earned between two or three times the federal poverty level—between $43,000 and $65,000 for a family of four—were without insurance at some point last year, an increase of 1.7 million since 2006. Even among households whose income was between three and four times the official poverty level, approximately $65,000 to $87,000 for a family of four, more than one in five adults were uninsured in the past 12 months.

The data exposes two myths about the uninsured, CDC Director Dr. Thomas Frieden explained. "The first is that only poor people are uninsured," he said. "The second myth is that only healthy people are uninsured—in fact, more than two out of five individuals who were uninsured had one or more chronic diseases."

The figures represent both a medical and social disaster.