Based on a representative sample of all U.S. families, a recent study of housework trends revealed husbands create an extra seven hours a week of housework for wives, but wives save husbands from about an hour of housework a week.

The study was part of the University of Michigan's Panel Study on Income Dynamics--the world's longest running study of it's kind--conducted since 1968, that collects data on the economic, health and social behavior of the same nearly 8,000 U.S. families year after year.

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The amount of housework done by women has decreased since 1976, while the amount of housework done by men has doubled. In 1976, women did about 26 hours of housework a week; in 2005, they did about 16.5. Men did about six hours a week in 1976, and in 2005, they did about 12.5.

Credit: University of Michigan Institute for Social Research

The amount of housework done by men and women varies according to their marital status. In 1976, single women, in all age groups combined, did nearly 19 hours of housework a week, and married women did nearly 28 hours. Single men did about 9 hours of housework a week in 1976, and married men did about 6 hours. In 2005, single women did about 13 hours a week, married women, regardless of age, did about 17 hours a week, single men did about 9 hours and married men did about 14 hours a week. These figures include all single and married men and women, regardless of number of children.

Credit: University of Michigan Institute for Social Research

This graph shows that in 2005, single women with no children did a little more than 10 hours of housework a week, and married women with no children did a little more than 17 hours a week. The only difference? The presence of a husband, which costs women seven hours of housework a week. For men, the situation is reversed. Single men with no children did about eight hours of housework a week, while married men with no children did a bit more than seven hours of housework a week. So a wife saves them about an hour of work a week.

Credit: University of Michigan Institute for Social Research

University of Michigan economist Frank Stafford tells us why women do most of the household chores almost 30 years after the original survey. He says the trend continues even though there are more two-earner families today than in 1976.

Credit: National Science Foundation