Nearly half of all Americans pay no income tax

From the Tax Policy Center:

Who Pays No Income Tax?

Nearly half of all families and individuals will pay no income tax this year. But who are they? It turns out that whether a taxpayer is single or married, is elderly, or has children makes a big difference. Nearly 47 percent of single tax units will owe no tax, compared with about 40 percent of joint filers and over 70 percent of household heads. About 55 percent of the elderly and tax units with children will pay no tax. Two factors primarily explain the variation: differences in income and available tax preferences.