Health insurance costs for the nation's workers skyrocketed this year, even as the quality of many plans deteriorated, according to an independent report released Thursday.

The average worker is now paying roughly $4,000 toward employer-sponsored family healthcare coverage "” a jump of $482 (14 percent) above last year's figure, according to the report. By contrast, overall premium costs rose just 3 percent above 2009 levels, researchers found, and employer contributions toward family coverage did not rise at all.

The findings "” stemming from an annual survey conducted by the Kaiser Family Foundation (KFF) and the Health Research and Educational Trust (HRET) "” are an indication that businesses have responded to the recession by shifting...