U.S. economic growth will slow significantly this year while inflation and interest rates both rise, but the country should be able to avoid a recession, the nation's top business economists predicted Monday. The National Association of Business Economists says a survey of its members found them slightly more optimistic about the economy's fortunes in 1989 than they were just three months ago. However, three out of four of the economists still believe President Bush will have to deal with an economic downturn in the first two years of his presidency. That represented a decline from the 89 percent who last November expected a recession by the end of 1990.