Hillary Clinton released her 2015 tax returns Friday morning, revealing that she and her husband paid an effective tax rate of greater than 40 percent in 2015 and donated just under 10 percent of their income of nearly $10.7 million to charity.

We are now less than 90 days from the November general election (hooray! hooray!) and yet have seen neither hide nor hair of her opponent's returns. Well, that's not totally true. We've seen an Instagram photo of Donald Trump signing a document next to a giant stack of paper, but the numbers on the papers are a bit hard to make out.

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Signing my tax return....

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And they don't tell us what we actually want to know: How much Trump gave to charity (and if it's more than $10,000), how much he has earned in recent years (and if it links to Russia) and what income tax he has paid (if any). We can answer these questions about every other Republican and Democratic candidate for president back to Gerald Ford — and we can say it for him, too, since he released a summary of what he'd earned.

The last Republican presidential candidate who didn't release his tax returns to the public was Ford, who never once won election to the executive branch. Ford had been a politician since leaving the Navy after World War II, so his returns lacked the sort of complexity or surprises that one might find in, say, the returns of a guy who has owned a huge, complex, multinational business for three decades.

Clinton has now, like all recent candidates, released both prior-year and past returns to the public. (You can find the last decade of returns here; the Clintons have previously released returns going back to 1977.) Mitt Romney — who also had a big, complex business — released his prior-year filings fairly late in 2012, as did George W. Bush in 2000, because of the blind trust that managed his assets. But Bush, as a governor, released returns even before he announced his candidacy, as did Al Gore that year, as vice president.

(Often, returns were released around April 15, when they are due, which is why so many of the dots above fall at about the 200-day mark.)

As you probably know, Trump says that he simply can't release his tax returns because they are under audit. I spoke with a former commissioner of the IRS who disputed that assertion and who noted that Trump could, at least, release returns from years prior to 2009, which are no longer under audit. Clinton has released a lengthy list of returns, back to her time as first lady. (The Tax History Project has all the past candidates' returns for your enjoyment.)

Trump clearly has no interest in releasing his tax returns. There's no law mandating that he do so. As with so many things this election cycle, we are reminded that much of the custom that surrounds our presidential campaigns is simply that: custom. Ignorable, and with little apparent price to pay for doing so.

With that in mind, we figured we'd at least try to track how long we'd been waiting to see Trump's tax returns. Since 1992, the longest America had waited until now to see a presidential candidate's returns was 415 days, between John McCain's (early) campaign announcement and his release after Tax Day 2008.

Trump has passed that mark.

If you're wondering, we're also tracking how long it has been since Clinton held a news conference. That's a rarity; though she's taken questions from reporters, she hasn't held an official one this year.

But I still feel pretty confident that it's more likely that Clinton's timer will reset before Trump's does.