Donald Trump has said repeatedly is that the U.S. should revisit its NAFTA agreement, because Mexico is “killing us on trade.” But the situation is much more complicated — and much less dire — than Trump suggests.

Yes, it is true that America’s trade imbalance with Mexico is at quite high right now in terms of dollars. Last year, for example, the U.S. imported $53.8 billion more of goods from Mexico in 2014 than it exported, per the U.S. Census Bureau. Over the first six months of 2015, the figure is $27.8 billion, which would pro rate out to $55.6 billion for the year.

At the same time, however, these figures are lower than average U.S.-Mexico trade imbalances for most of the past decade. The all-time high was $74.95 billion in 2007, and the trade deficit topped $60 billion for six of the seven years between 2006 and 2012.

But most important, the top-line number is not really the best way to determine the severity of the U.S.-Mexico trade imbalance. Instead, you want to look at how large the deficit is in comparison to the amount of U.S. exports to Mexico.

And when you look at those numbers over time, Trump’s claim doesn’t really hold up.

Last year’s U.S.-Mexico trade deficit represented 22.4% of all U.S. exports to Mexico. For the first half of 2015, the figure is 23.7%. Back in 1985 — one of those ‘great’ years to which Trump hopes to return — the $5.5 billion trade deficit represented 40.3% of all U.S. exports to Mexico. In 1995, the $15.8 billion trade deficit represented 34.1% of all U.S. exports. In 2005, the percentage was 41.4%.

If Trump wants to argue that U.S.-Mexico trade relations have been lousy for the better part of three decades, then that’s an argument he’s free to make. But he regularly implies that the imbalance is a failure of current leadership. It actually would go back over at least three decades and multiple presidents of both parties. And Trump has not yet explained how he’d do better.

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