How many households does it take to make a campaign ad?

One of Senator Barack Obama’s campaign ads claim that Senator John McCain offers no tax relief for 101 million families.

According to the the United Census Bureau’s American Community Survey 2007 there were 112 million households in America last year, 75 million of which were family households, 35 million of which had children under the age of 18 living in it (that is, were families with kids, the kind of set up that most people probably think of when they picture a family, especially given the context).

The corresponding numbers in the 2000 population count were 105 million, 72 million and 35 million.

Regardless of which kind of household one talks about a good number of them doesn’t pay any federal income tax and therefor really can’t be the recipient of federal income tax cuts. Many households, especially family households, that file for income tax but don’t earn enough to owe any instead receive cash from the government through the Earned Income Tax Credit (which is a mighty good program, if you ask me, even if it carries with it severe marginal tax rates and probably undesirable labor market consequences as well).

According to the left leaning Tax Policy Center the bottom quintiles had a negative federal income tax in 2007, ie. they received money from the government (the middle quintile had a mere 2.8 percent tax rate so I imagine about half of all households don’t pay any federal income tax (they would be what one Wall Street Journal editorial writer called “the lucky duckies.” They are such friends of working people at that newspaper)).