The National Tax Administration Agency said Friday that 926 public-interest corporations, including those running private schools and temples, failed to declare 16.443 billion in corporate income for the July 1996 to June 1997 period.

The corporations accounted for 72.6 percent of the public-interest corporations that were subjected to tax investigations, the agency said. Although they are taxed at a lower rate, the number of corporations that failed to declare their full corporate income for the last July-June period increased 3.2 percent from the previous year's 897, but the aggregate amount of undeclared income was down 18.9 percent from the previous year's 20.270 billion yen.

About 23,000 of Japan's 254,000 public-interest corporations declared incomes. Some 1,276 of them, including 517 religious corporations, were subjected to tax investigations, according to the agency. Of the 926 corporations in question, 94 were found to have concealed a total of 805 million yen, the agency said.