New Census Bureau figures show that the gap between the rich and the poor is widening, says the chairman of the congressional Joint Economic Committee.

"Those at the top of the scale are receiving an ever-larger share of the pie," Rep. Lee Hamilton, D-Ind., said Wednesday after the bureau released its annual report on income and poverty."Meanwhile, families in the middle and at the bottom are barely keeping ahead of inflation," Hamilton said. "The gap between the rich and the poor is widening when it should be shrinking."

Robert Greenstein, executive director of a liberal research group, the Center on Budget and Policy Priorities, said the 12.8 percent poverty rate reported by the bureau is a bad sign.

"With the economy running out of steam and a new recession threatening, the poverty rate is likely to start rising again," Greenstein said.

Both liberals and conservatives continued to clamor for a change in the way the Census Bureau figures out who is poor.

For the third year in a row, the bureau said the decline in the poverty rate between 1988 and 1989 was so small that it was not statistically significant. The 1988 rate was 13 percent.

The bureau said 31.5 million Americans were below the poverty level last year. For a family of four, that level is an annual income of $12,675. In 1988, 31.7 million were below it.

"It is time to update our official poverty measure to provide a more accurate reflection of today's economic needs," Hamilton said.

A Joint Economic Committee study last year suggested that the poverty thresholds might increase as much as 50 percent if they took into account such things as the increasing share of income that is now paid for housing.

On the other hand, Kate O'Beirne, deputy director for domestic policy studies at the conservative Heritage Foundation, said, "Owing to the method they use, the Census Bureau dramatically overstates the number of people in poverty."