The national medical bill rose last year to $287 billion or 9.8 percent of the gross national product, meaning health care took nearly $1 of every $10 Americans spent, the government said yesterday.

Health care costs rose 15.1 percent in 1981, the second largest increase in the past 15 years. The 1980 increase, according to newly revised figures, was 15.8 percent.

The new figures from the Department of Health and Human Services are a further sign that efforts by the last several administrations to slow the rise in health care costs so far have failed.

HHS Secretary Richard S. Schweiker, in a statement accompanying the report, gloomily conceded that health care costs are increasing "well above the rate of inflation," adding that "these disturbing figures are the strongest argument for reforming the existing system of health care cost reimbursement."

Schweiker has sent the White House a plan to restructure the current system of financing health care in an effort to bring down costs. It would increase competition among providers of medical services and put limits on provisions in the tax code that, it is argued, encourage excessive use of doctors and hospitals.

While health care costs rose 15.1 percent last year, Medicare costs rose 21.5 percent, the new report said. Medicare for the elderly and disabled is the largest of the government health programs, and one in which Congress is now trying to legislate significant cuts.

In 1965, according to yesterday's report, health outlays were only 6 percent or a little under one-sixteenth of GNP. Health outlays per person rose from $211 in that year to $1,225 last year.

HHS said that about three-quarters of the 1981 cost increase resulted from inflation, about 7 percent from population shifts and increases and about one-fifth from greater "intensity of care." That increase in the "intensity of care" meant there were more tests, more doctor visits and more of everything connected with health care for each patient.

A key factor in the 1981 increase was the 17.5 percent increase in hospital costs.

U.S. health outlays as a proportion of GNP are a bit higher than those of many other industrial countries but lower than West Germany's, according to the Social Security Administration.

In 1976, U.S. health outlays were about 8.7 percent of GNP while the figure for West Germany was 9.4 percent, for France 8.2 percent, for the United Kingdom 5.8 percent, for Canada 7.1 percent, for the Netherlands (l975) 8.6 percent and for Sweden (1975) 8.7 percent.

Most of these countries have national health insurance, so the proportion of medical costs paid by government funds is much higher there than the more than two-fifths that is paid for by the government in the United States. In West Germany, for example, according to a recent book ("Health and Wealth" by Robert J. Maxwell), government at all levels paid about 77 percent of all medical costs in 1975. In Sweden the government paid 92 percent.

Of the $287 billion spent on health care in the United States in 1981, $122.5 billion or nearly 43 percent came from federal, state and local government funds. That included $73.2 billion from Medicare and Medicaid alone, which, by themselves, accounted for over one-quarter of all health spending. Of the total, $118 billion went to hospitals, $55 billion to doctors, $24 billion to nursing homes, $21 billion to suppliers of drugs and medical sundries and $13 billion to research.