Last week, I cited IRS data and noted that tax evasion has likely added somewhere between $3 trillion and $5 trillion to the national debt over the last decade -- more than the Bush tax cuts, the wars in Iraq and Afghanistan, and the Obama stimulus combined.

"It's amazing more people aren't outraged about this stuff," I wrote. "Rather, they likely would be if they knew about it."

Not so fast, one reader warned. "What [percentage] of people evade taxes? Any estimates? I wouldn't be surprised if it isn't over 50%. It's hard for someone to get outraged about something they do themselves," the reader wrote.

We'll probably never know exactly what percentage of tax filers cheat. When the IRS estimates (PDF file, Adobe Acrobat required) the "tax gap" -- the amount of taxes that should be paid, but aren't -- it notes that the voluntary compliance rate is around 83%, meaning 17% of taxes owed are illegally evaded.

But that doesn't tell us what percentage of tax filers are actually cheating -- just the dollar amount of taxes underpaid. The IRS Oversight Board does, however, run a poll every so often asking taxpayers how they feel about tax evasion. Here's what people said last year:

Source: IRS Oversight Board.

It might be hard to take these results seriously. If asked by someone representing the IRS whether it was OK to stiff the IRS, most people can harness the power of second-order thinking and realize that the correct answer is "no," regardless of whether that's how they actually feel.

So let's take an informal (and totally anonymous) poll. Do you feel it's OK to cheat on your income taxes? Weigh in below, and share a thought or two in the comments section if you so desire.

Fool contributor Morgan Housel doesn't own shares in any of the companies mentioned in this article. Follow him on Twitter @TMFHousel. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.