The world's population by the end of this century will be close to 6.1 billion, of which almost 80% will be living in developing countries, a U.N. report said. Global population is currently estimated at 4.8 billion. The report said the growth rate is expected to decline more slowly than in the last 15 years unless government population policies change significantly. The annual gain is expected to increase from 79 million at present to 89 million by the years 1995-2000. Among 33 advanced countries, 25 had a decrease in their growth rates between the early 1970s and the early 1980s and six had no significant change.