Hospital expenditures rose by about 12.8 percent during the first half of this year, 2.8 percentage points less than the rate for 1977, according to health-care industry spokesmen, who credited the drop to their voluntary cost-cutting efforts.

Overall hospital expenditures this year will be about $59.7 billion, compared to last year's $53 billion, they said yesterday.

"The decrease in the rate of increase" through July of this year indicates that the profession will surpass its self-imposed goal, which was a 2 percentage-point reduction in the rate of increase, according to Paul Earle, director of a voluntary than when they are imposed through government mandates such as the cost-containment legislation that failed in the 9th Congress.

The voluntary committee said the effort has saved $900 million this year and will reduce expenditures by $44 billion in the next six years.

In addition, physicians are exhibiting a willingness to cut their fees, according to AMA spokesman James Sammons. Doctors have pledged their compliance with the AMA president's call for a reduction of 1 percent a year in fee rate he said.

The voluntary effort has spawned similar cost-control efforts in every state since it was formed last year in the face of impending legislation to counter the soaring costs of health care.

In addition to cutting back the increased in hospital expenditures, the committee's goals are no additional hospital beds this year and capital expenditures of no more than 80 percent of the past four years' average, according to Earle.

Members of the voluntary committee said the 1978 hospital cost rise of less than 13 percent was the lowest since government controls under the Economic Stablization Program were removed in 1974.