Take my advice on this and don't trust the data from either side, it can be absolutely true and utterly bullshit at the same time. They generally drink their own kool-aid at think tanks. Except for the ones who cheerfully manufacture crap their employers want to hear, which from my own experience is not too rare. And the TPC is not even vaguely non-partisan, unlike conservative Heritage or Libertarian CATO or liberal Center for American Progress who openly proclaim bias, TPC just likes to claim it. Which makes me trust them even less, especially since it's a bald-faced lie, which always makes me distrust the accuracy of someone's subsequent data and analysis for some reason.

You're best off just going with CBO data by household income IMHO. That has limited utility, but it's exactly what it says on the tin. All these various extraction people make, even when factual accurate, are essentially bullshit. Everyone pays taxes and everyone receives benefits, the goddamn road to someone's mansion and the navy that protects their cargo ships from getting hijacked are, in fact, 'benefits', just like a taxpayer funded education or a welfare check or EITC or access to a fair trial before a jury of your peers where a lawyer will be provided and the cops won't torture confessions out of you. These are benefits, they cost money, that money comes from somewhere and we wouldn't have millions of lines of tax code if it was 'easy' to figure out who was paying it. A 20 cent hike to cigarette tax is a regressive tax, more so since poor smoke more, gas tax borders on it, ditto booze and soda, and state lotteries are amongst the worst offenders in terms of percentage of income the poor spend on those relative to the rich. These ultimately have to be considered taxes as they generate revenue for government, and that they are voluntary to one degree or another doesn't really matter if only a quarter of the poor pay them. At least not if one's goal is to not tap the poor for revenue. Taking money from someone you will then send it to is pretty ass-backwards even if you didn't have to employ people to attend to that.

From a conservative perspective, proving "86% of Americans pay payroll or income tax" merely highlights a retarded taxation system... that incidentally is a blatantly wrong comment, as 86% of Americans aren't even all over 18, actually 20% of Americans are under 14... generally very few of those pay taxes. Of course 86% of American *Adults* do not either, what with the 9% actively seeking work, I'd bet more than the remaining 7% fall into the categories of 'gave up' at the moment but then quite a few not seeking work at all because they are kids, retired, stay-at-homes, in jail, etc. There are under 150 Million people working in this country, one presumes that they are the only ones actually paying payroll taxes and probably not all of them and that the other 165 odd million do not, for one reason or another, and those reasons are either totally valid, totally invalid, or marginal depending on the person. These sorts of studies do usually fine print such things to remain technically accurate then someone from whichever party or group they shill for comes by and writes an article or gives an interview omitting the part fine print part and leaving out all the other factors which inconveniently would poke holes in their claim.

For instance a lot of these studies are actually 'by household', and they derive their data from the CBO, who typically just break households up by income with out comparing by size. A 7 person household in the middle quintile for income is probably not doing as well as single person in the quintile below them, but even then one would have to check what subsidies they might be receiving, like EITC, and it is simply damned retarded to just add in EITC when a single college student might be getting grants paying for their room and board and schooling for instance. I've pretty much given up on the idea that there actually is anyway to determine if the taxes are fairly distributed partially because of the complexity and hidden taxes, but mostly because I have yet to figure out exactly what 'fair' actually is, is it a head tax where everyone pays the same? Not really fair if others get more services even if one assume the rich shouldn't pay more. Is it a percentage everyone pays that's the same? The wealthy will pay way more but still have a larger percentage of their income available for beyond subsistence, a higher rate by income? A flat tax with deductions for the minimum standard of living? I really have no idea. Heck even dumping debt on the next generation isn't entirely unfair, they are a large percentage of the spending and they are benefiting from all those new technologies developed on a lot of those dollars, via research, investment, or consumption... I'd have no problem if cancer got cured twenty years earlier by running a debt on it. No clue what's actually fair. I am pretty sure that effectively massaged numbers are a piss-poor way of determining that though... </rant>

Short version: Most of the people quoting data at you on this subject are telling you absolute garbage that they firmly believe is true and quite often is true, but it's still garbage.