I have already sent in my vote for president of Mexico. Because I live abroad, I could do it by mail. This is the first time ever that I have voted (in Mexican elections). But I had an advantage that few other Mexicans have: I was able to speak personally with the three principal candidates who are running for president.

It is certainly one of the privileges of being a journalist. Before I voted, I wanted to know how much money the candidates have. For me, it seemed an important question.

For some reason that I have yet to fully grasp, all former Mexican presidents are millionaires. How could that happen if for years they lived on modest public servant salaries?

If we know how much each of the candidates has in assets today, we can calculate how much money the winner accumulates by the end of his six-year term.

Let's start right now.

The candidate who seems to live most modestly is Andres Manuel Lopez Obrador, from the left-leaning Democratic Revolution Party.

"Well, in cash, I must have about $35,000 pesos (about US$3,500)," he told me in an interview while he was still Mexico City mayor. "But I own the apartment where I live in the city and a house in (the state of) Tabasco; that's, basically, what I have."

I bumped into Lopez Obrador again a few days ago in the Mexican capital and he was still driving around in an old Nissan Tsuru. The only difference now is that two bodyguards were parked in the back seat.

"I live frugally," he told me. "I have no ambition for more money than I need to live, and to support my family."

I asked Felipe Calderon, the candidate from the ruling National Action Party, the same question: "How much money do you have?

"Look, I have approximately $340,000 pesos in the bank, that is, US$32,000, more or less," he replied during a talk at his campaign headquarters. "I live in my own house, which must be worth about $380,000. My wife has a similar amount in her bank. And that's roughly what I have."

Calderon and his wife together, therefore, have about $750,000 dollars "earned honestly," as he confirmed. "My hands are clean; I am a man who has spent 20 years in public office, who has built up savings honorably (to leave to my children)."

"Might you be considered the candidate of the rich?" I asked.

"Those are two different things" he answered. "I am the only candidate who has authorized the IFE (the Mexican Federal Electoral Institute) to screen any bank in Mexico and abroad for assets that I may own. I am the only one who has nothing to hide."

Roberto Madrazo, from the Revolutionary Institutional Party, seems to have more money than the rest of the presidential candidates put together.

"The perception is that you live like a wealthy man in spite of being a public servant all your life; that is the suspicion," I said to Madrazo during a conversation in his van, on the way to a campaign event in south Mexico City.

"That is a fable," he replied. "I have nothing more than what I have. I have never hidden what I have."

"How much is it?" I pressed him.

"Enough" he answered. "I have enough. It is all listed on my assets declaration."

"Why don't you want to specify how much?" I asked him, after assuring him the other two candidates had already told me what they owned.

"It is almost $30 million pesos," he said, finally. "That is close to US$3 million," he stressed, "earned through companies, and my law firm."

According to him, that amount must also include the two properties he owns in south Florida. "It is not one, but two," he emphasized.

When I asked him whether his personal fortune could generate suspicion that he took advantage of his public posts in order to make money and do business, he said he "would be in jail" if that were the case.

"A person who takes advantage of public office should be in jail, not free on the streets," he said firmly.

Madrazo concluded: "I have not lived on my earnings in public office. And I want to tell you right away that I do not live off politics. There are politicians who make a living out of politics. Not me. That is why I want to be president, because I do not depend on politics (for my income)."

So that's it. Now we know how much each of the three main candidates running for president claims to have. Let's hope the sums come out right.

I don't know what'll happen to the losers, but regarding the winner, we will most certainly add things up in 2012 _ to be certain that, unlike other former Mexican presidents, he does not emerge from Los Pinos (the presidential residence) a multimillionaire. I say this, just in case.