The Conference Board also reported that consumer buying plans fell last month. According to the New York-based business research organization, the reports indicate that economic growth will be modest through the first quarter of this year. The organization said its consumer confidence index, with a base of 100 in 1985, fell to 97.3 last month, down from 99.8 in December. About 27% of consumers surveyed regarded January business conditions as good, down from about 29% in December. Plans to buy a home fell to 3.6% in January, down from 3.9% in December, and plans to buy a car within six months fell to 8.9% last month, compared to 10.2% in December, the group said.