If you treat everything described in ordinary conversational English by an airline ticket as the same, you can get some decisions right, but for many, you need to discriminate within the broad category. Same with taxes: Mitt Romney pays sales taxes, property taxes, automobile and gasoline excise taxes on at least a pair of Cadillacs, state income taxes, airline ticket excise taxes, others I can’t think of at the moment, and federal income tax. He and his spox have meticulously said “taxes” without qualification when everyone is thinking about the last of these; today, he did it again, saying he never paid less than 13%. Even if he means “income taxes”, Massachusetts income tax is more than a third of that, and we don’t even know what denominator he’s referring to (AGI, gross income, taxable income) or whether he’s talking about his marginal rate or average.
Why has no reporter ever insisted he define his terms in this very salient conversation? It’s very simple - “Have you ever paid less than 13% of your annual gross income in federal income taxes?” – and not doing it is simply journalistic malpractice.

[...] addition, as Michael O’Hare notes, Romney said he paid 13% “in taxes.” He did not specify. Is that on adjusted gross [...]
Rmoney’s campaign said later that it was federal income tax [for what that source is worth]. And even this seemly clear statement does not include unrealized capital gains.
But that still leaves us with “what is his gross income?” The IRA and other dodges tax exempt a large portion, we know this from the released form.
Without tax forms we can only speculate based on the most cleaned up tax return. Even Harry Reid’s source did not see the 2002-2011 taxes Rmoney is describing. Reid’s source saw at best 2003 and earlier, when Rmoney was at Bain. The press and discussions almost always miss this.
On an earlier discussion someone mentioned that the IRA [I believe they referred to it as a 401, which it is not] will begin distribution in 2017 and be taxed at the top rate. That is naive. It will be made into a Roth. If Rmoney elected to convert to a Roth, the penalty would be the top rate of 35%, unless the top rate were to drop to say 25%, but then who is so criminal to propose that?
One might even see a one time conversion special to allow conversion to Roth at say 10%. For the year of the conversion special, a large influx of one time revenue would make that year look good for say maybe an election.
http://www.spencerlawfirm.com/Publications/Mitt-Romneys-IRA.shtml
http://www.forbes.com/sites/joshbarro/2012/01/19/why-didnt-mitt-romney-convert-his-ira/