Mitt Romney is so desperate to get you to forget the phrase “47 percent” that he’s introducing an entirely different percentage meme today: 13.66 percent. That’s the lowest effective income-tax rate Romney paid between 1990 and 2009, according to a notarized letter from Romney’s tax preparer summarizing Romney’s tax information. The tax returns from those years remain undisclosed, but Romney will be releasing his 2011 tax returns, only just filed with the IRS, at 3 p.m. That will show that in 2011 Romney paid an effective income-tax rate of 14.1 percent. All this information will be made available here. (I’m working off an advance leak to the Wall Street Journal.)

If the 13.66 percent figure is correct, then Senate Majority Leader Harry Reid was wrong when he accused Romney of having paid no income tax over a ten-year period. There wasn’t even a single year in which Romney paid zero taxes. However, 13.66 percent is a pretty low rate. During those years Romney’s fellow one-percenters paid more like 20 percent. Assuming Romney’s tax preparer signs that notarized letter to be released at 3 p.m., he may find himself picking up a lot of new customers for 2012.

The most surprising finding is that the Romneys last year gave nearly 30 percent of their income to charity—most of it presumably to the Mormon Church, to which they tithe income. Thirty percent is a lot of income to give away. It’s more than twice the 14.1 percent they gave to the IRS. It’s also seriously out of whack with their usual charitable contribution level, which between 1990 and 2009 averaged an already-impressive 13.45 percent. Indeed, the Romneys claimed a tax deduction on only a little more than half the $4 million total, presumably to avoid ending up with an even more embarrassingly low effective tax rate. Whatever the difference was, it constituted an unofficial contribution to the Romney-Ryan campaign. But I doubt the Federal Election Commission will bother the Romneys about that.