An annual tongue-in-cheeck "cost of laughing" index jumped 5 percent during the past year, meaning "we're paying more to laugh less," a humor consultant reports.

A "saucy secretary" singing telegram by Eastern Onion in New York jumped from $55 to $65 while the wholesale price of rubber chickens remained steady at $48 a dozen, reports Malcolm Kushner, an attorney-turned-humor consultant.Kushner said he uses a survey of 18 humor indicators to determine the index, including admission to 10 comedy clubs in selected cities and the wholesale prices of rubber chickens, Groucho glasses and arrow-through-the-head gags. A 5 percent increase, said Kushner, is no joke. "Adjusted for inflation, it means we're paying more to laugh less."

Kushner is a Santa Cruz, Calif.-based humor consultant to such corporate clients as IBM, Hewlett-Packard, Lockheed and the Internal Revenue Service and gives advice on how to use levity as a management tool. "Whether or not you think the world needs a humor consultant, it can definitely use one less attorney," he said.

The yearly Cost of Laughing Index, he said, was developed several years ago to track how the punch line affects the bottom line and is issued in time for April Fool's Day.

"This year's index has some good news and some bad news," said Kushner. "The good news is rubber chicken prices have stablized after jumping 23 percent between 1986 and 1988. The bad news is they're still too expensive to come home to roost."

Comedy club tickets, he noted, have risen an average 6.9 percent to average about $9 while

Groucho glasses were the same at $12 a dozen, and arrow-through-the-head gags at $5.40 a dozen.