Nearly one in five Americans think cheating on taxes is morally acceptable or is not a moral issue.

Some 10 percent are equally ambivalent about cheating on a spouse.

In a survey by the Pew Research Center released today, 88 percent of respondents said it was morally wrong to have an affair. Not reporting all income on taxes was called morally wrong by 79 percent of the people.

The flip side: Three percent said affairs are morally acceptable and 7 percent said they are not a moral issue. For tax cheating, those numbers were 5 percent and 14 percent, respectively.

Survey respondents were read a list of ten behaviors and asked whether, in their personal opinion, each one is "morally acceptable, morally wrong, or not a moral issue."

The percentage who called other activities morally wrong:

Drinking alcohol excessively: 61 percentHaving an abortion: 52 percentSmoking marijuana: 50 percentHomosexual behavior: 50 percentTelling a lie to spare feelings: 43 percentSex between unmarried adults: 35 percentGambling: 35 percentOvereating: 32 percentThe telephone survey of 1,500 adults was conducted in early February. It has a sampling error of plus or minus 4 percent.

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