Mitt Romney's 47 percent is now 45.3 percent.
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.
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."
Williams added in a Tuesday blog post that the Center, the Joint Committee on Taxation and the Treasury Department all do a good job estimating who's not paying income taxes. The trickier problem to figure out, he said, was who's not filing returns at all.
The Tax Policy Center also continues to believe the amount of taxpayers not owing income tax will fall, but not as swiftly as it previously thought. Most people who don't pay income taxes are working and therefore do contribute payroll taxes.
For a variety of reasons, top GOP presidential candidates this time around are proposing tax plans that would give some assistance to lower-income voters.
Former Florida Gov. Jeb Bush would take millions off the income tax rolls, mostly by increasing the standard deduction. GOP front-runner and billionaire businessman Donald TrumpDonald TrumpTrump won't comment on Le Pen Macron’s success in France signals hope for unifying outsiders French election: Le Pen, Macron ahead in early results MORE is also offering a zero percent income tax rate.
Both candidates' tax plans would offer far greater tax cuts to the highest earners.