In more than half of American families, both the husband and wife work, the Labor Department said. Its Bureau of Labor Statistics said husband-wife working combinations existed in 52.2 percent of families in 1979. Ten years earlier, husband-wife earning combinations represented only 45.8 percent of households, according to census data. The bureau said the number of married women in the labor force soared by nearly 6 million during the '70s. By last March, 24.4 million wives were working or looking for work.