US Policy Faulted for Slow Global Economy THE world's economy will grow more slowly this year than last - and more slowly than previously predicted - in part because of faulty United States monetary policy, a United Nations agency said Monday. Global growth this year should be 2.9 percent, compared with 3.7 percent last year, the UN Conference on Trade and Development (UNCTAD) said. As recently as April, the International Monetary Fund had predicted a growth rate of 3.8 percent. In its annual trade and development report, UNCTAD criticized the US Federal Reserve for trying to stem inflation by raising interest rates. It said the rate increase slowed the economy too much. There are ''still no clear signs that inflation threatened,'' UNCTAD said. In the past, the agency said, labor unions could win wage increases during economic recoveries, driving up prices. But unions have lost power, and inflation is no longer an inevitable consequence of economic recovery. The agency also said that because of increased global competition, many workers fear demanding higher wages because they could price themselves out of a job. UNCTAD also warned of high unemployment and said governments are doing little to attack it. The jobless rate for wealthy countries has averaged 7.3 percent over the last 15 years, compared with 3.2 percent during the 1960-73 period. ''Unemployment is reaching politically menacing levels, threatening to bring social disintegration and beggar-my-neighbor policies and jeopardizing the stability of the international trading system,'' the report said. While some countries have been able to create new jobs, most have been of poor quality, the report said. ''In the United States, for instance, employment has grown significantly faster than in most other industrial countries, but most of the new jobs created are low-paid,'' it said. Pay increases will hold in '96 AMERICANS can expect the average increase in their take-home pay to hold steady at just above 4 percent next year, reports a recent survey by Watson Wyatt Worldwide in Wellesley Hills, Mass. ''With inflation expected to remain in the 3 percentage range, 4 percent raises are not as meager as they might look on the surface,'' notes Ira Kay, director of Watson Wyatt's compensation consulting practice. The survey of 1,814 organizations shows that planned increases in 1996 range from 3.1 percent among nonprofit organizations, to 4.6 percent in the computer programming and software sector. Gas prices fall slightly, again The smallest drop yet in a steady three-month decline in gas prices has occurred over the last two weeks, with rates falling about a half-cent per gallon. The average price, including all grades and taxes, was $1.2011 per gallon last Friday, compared with the Aug. 25 average of $1.2073, a drop of 0.62 cents, said Trilby Lundberg, publisher of the twice-monthly Lundberg Survey. Since June 9, prices have declined a total of 8.51 cents, said Ms. Lundberg, who polls 10,000 gas stations nationwide. For the same period in 1994, prices jumped 7.64 cents.