The Tax Policy Center says that’s now the number of households who don’t pay any income taxes, an almost five percentage point increase over the 2013 estimate of 40.4 percent.

Romney, the 2012 GOP presidential nominee, took a political hit when he used a previous Tax Policy Center estimate to assert that the 47 percent who didn’t pay income taxes would support President Obama.
The Tax Policy Center, a joint venture of the Urban Institute and the Brookings Institution, says this year’s increase is largely due to more precise projections about who actually pays taxes.

In other words, as the Center’s Roberton Williams put it: “Those additional non-payers were there all the time — we just failed to count them.”