One aspect of inflation that the government appears to have under control is its tendency to crank out press releases. Washington Researchers, a research and publishing firm here, keeps what it calls the Federal Press Release Index, and this index, unlike the better-known consumer price one, has been going down. Taking 1971 as a base (equal to 100), Washington Researchers find that the press release index has declined by more than a quarter -- to 73.7 last year. Only the Labor Department (127) and the Civil Aeronautics Board (119) are running above their 1971 levels. The decline has come during a period when federal expenditures climbed 36.3 percent in terms of 1971 dollars, Washington Researchers say. And, they calculate, the amount of information the government generates -- real information, such as technical publications, pages in the Federal Register, congressional printing, as distinct from press releases -- has climbed 96 percent. Washington Researchers don't view this as all to the good, however. "The federal government is the largest generator of information in the world and the amount of information it generates continues to increase . . . However, the . . . government devotes very little of its resources to advertise the availability -- usually at low cost -- of information . . ." they say.