The population of the Soviet Union rose to 284.5 million at the start of 1988, an increase of 4.8 million over 1978, and the average Soviet citizen can now expect to live 69.6 years, Tass said Saturday.
The official Soviet news agency, quoting data from the State committee for Statistics, said the average life expectancy had risen by almost two years but did not say over what time period.
Average life expectancy for Americans is more than 71 years. Western specialists attribute the lower Soviet figure to living conditions that have traditionally been harsher, fatal industrial accidents, alcoholism, a colder climate and other factors.
On Jan. 17, 1987, Tass said the population was 281.7 million.
The Soviet life expectancy statistic was once regarded as so sensitive it could not be published. But in May, the weekly magazine Ogonyok reported that near the end of the 1970s the average life expectancy of men fell to 62 years. It said the downward trend was halted, then reversed in the early 1980s.
Tass credited the changes wrought by Kremlin economic and social reforms, including the "ensuring of a priority development of the social sphere," for the improved demographic outlook.
Past reports in the official media have said the anti-alcohol drive launched by Soviet leader Mikhail S. Gorbachev has led to a decline in the mortality rate and a drop in industrial accidents.
Tass said that in 1987 the Soviet mortality rate had "perceptibly declined," but gave no details.
Official media reported in August that the death rate had fallen by 20% in 1986 as compared to the previous year, but gave no figures.
In the last several years, the Soviet Union has increased benefits for large families and extended some new benefits to mothers for up to 1 1/2 years after birth to encourage couples to have children.
In the United States, 3.71 million live births were reported in 1987, down from 3.77 million in 1986. The U.S. population was 243.4 million in mid-1987.
Because of the increased births and lower death rate, the Soviet Union's annual population growth rate increased to 2.9 million in 1986-87, up from 2.4 million in 1981-85, Tass said.
Tass did not specify where the country's population growth had been strongest.