Fast-rising health care costs have consumed nearly all the income gains made by a median-income American family of four over the past decade, leaving them with just $95 per month in extra income, after accounting for taxes and price increases, according to a new RAND Corp. study.

Had health care costs risen only as fast as the cost of other goods and services in the United States from 1999 to 2009, the same family would have had an additional $545 per month to spend in 2009.

Between 1999 and 2009, total spending on health care in the United States nearly doubled, from $1.3 trillion to $2.5 trillion. During the same period, the percentage of the nation's gross domestic product devoted to health care climbed from 13.8 percent to 17.6 percent. Per person health care spending grew from $4,600 to just over $8,000 annually.

Although the numbers are sobering, they aren't immediately visible to American families because many costs are hidden, according to researchers. Health care costs are visible to American families in two ways — through the monthly premium they pay for their share of private insurance and through out-of-pocket spending for co-payments, deductibles, medications and other health care items.

But other costs are not so obvious, researchers say. One is an employer's share of the family's premium for private health insurance, which in effect reduces an employee's wages and other compensation. The second is the portion of a family's federal and state tax burden that is devoted to government programs such as Medicare, Medicaid and military health care.

While the median-income American family experienced a 30 percent gain in income from 1999 to 2009 (from $76,000 to $99,000 annually, or an increase of $1,910 monthly), health spending grew much faster. The family's monthly health insurance premium grew by 128 percent (from $490 to $1,115), and out-of-pocket spending rose 78 percent over the period (from $135 to $240).

On a monthly basis, the family's income grew about $1,910. More than 40 percent of that increase was spent on higher health care costs. Nonhealth care taxes and increases in the cost of consumer goods absorbed another 52 percent. This left the typical median-income family with a $95 increase in disposable income.

For more information, go to www.rand.org.