Still the champ: Ford's F-150 is the most American vehicle, says a new report. Source: Ford Motor Co.

What could be more American than a Ford (NYSE:F) F-150?

Not much, according to the latest edition of's annual ranking of the top American-made vehicles, which ranked the F-150 in first place.

The "American-Made Index" is an annual listing that ranks vehicles on three key points: Where they're built, where their parts come from, and how many are sold in the U.S. 

It's no surprise that the F-150 tops the list. The stalwart pickup and its Super Duty siblings have been America's best-selling vehicle line since the Nixon Administration. 

But this might be a surprise: It's the only Ford on the list.

Why the F-150 is as American as it gets
As I said above, the analysts look at three factors when building the list, and none of those factors has anything to do with the company that made the car.

Vehicles that aren't built in the U.S., that are about to be discontinued without a U.S.-made successor, or that have "domestic parts content" of less than 75% are disqualified from consideration. (The "domestic parts content" rating is calculated according to a formula set out in U.S. law. It counts the percentage of the vehicle's parts that come from either the U.S. or Canada.) 

The limit on domestic parts turns out to be a killer. Only 10 vehicles made the list at all this year, the lowest number ever.

But it's not a surprise that the F-150 led the list. Ford sells a lot of F-Series trucks, over 60,000 of them in most months. That means Ford needs to make a lot of them, and it does. The company has two factories building the F-Series, one in Dearborn, Mich., near Ford's headquarters, and one in Claycomo, Mo., near St. Louis.

Ford's Americas chief, Joe Hinrichs, recently told me those factories produce 60 trucks an hour. Both work three shifts -- 120 hours a week, plus overtime when needed. 

At that relentless pace, it makes sense that Ford would want the trucks' parts made close by -- so it's no surprise the F-150 has a high domestic parts content. And unlike most Ford products nowadays, the F-Series is only made in the U.S.

But why is it the only Ford on the list? And why did two Japanese brands take seven of the 10 spots?

How Toyota and Honda beat Detroit
Here's the full list of vehicles that made the list, along with the locations of the factories that make them:

1. Ford F-150: Dearborn, Mich. and Claycomo, Mo.

2. Toyota Camry: Georgetown, Ky. and Lafayette, Ind.

3. Honda Odyssey: Lincoln, Ala.

4. Toyota Sienna: Princeton, Ind.

5. Toyota Tundra: San Antonio, Texas

6. Toyota Avalon: Georgetown, Ky.

7. Chevrolet Corvette: Bowling Green, Ky.

8. Honda Ridgeline: Lincoln, Ala.

9. Honda Crosstour: East Liberty, Ohio

10. Dodge Viper: Detroit, Mich.

As you can see, Toyota and Honda (NYSE:HMC) took seven of the 10 spots, with Detroit represented only by the F-150 and two sports cars. 

How did that happen?

America's most American car? says it's Toyota's Camry. Source: Toyota.

There are a few things to think about. First and foremost, the Toyotas and Hondas that made this list are models designed primarily for the U.S. market. It's in both companies' interest to make them here -- and because they're only made here, it makes sense to get the parts from local sources.

It's also in both companies' interest to make their key products as "American" as possible. While prejudice against "import" brand isn't as big a deal as it once was, Toyota and Honda have both long followed a strategy of downplaying their Japanese roots as they market to American buyers.

Using a high percentage of American-made parts and building these models in American factories gives their dealers a way to overcome objections from buyers who might be predisposed to "buy American."

But why aren't there more American-brand cars on the list?
It's hard to say. But I suspect at least one part of the answer comes down to one word: Mexico.

All three of the Detroit automakers, and plenty of others, have big operations in Mexico -- as do key suppliers of parts to the automakers. Fiat Chrysler's (OTC:FIATY) Hemi V8 engines may seem all-American, but they're really made in Mexico -- as are cars like the Ford Fiesta, and many of the Ford Fusions sold here.

The Dodge SRT Viper sells in tiny numbers -- just 354 so far this year through June -- but its Detroit factory and 75% domestic parts content was enough to put it on the list. Source: Fiat Chrysler.

Under the North American Free Trade Agreement, it's easy for U.S.-based businesses to do business in Canada and Mexico, and relatively low labor costs have made Mexico especially attractive to U.S.-based manufacturers in recent years. 

It's likely that if we counted Mexican-made parts and vehicles as "domestic," we'd see a lot more vehicles on this list.

Of course, Mexico isn't the U.S. But if we're not counting Mexico, why count Canada? 

It turns out that's a question for Congress. notes that while there are several different ways to count "domestic parts content" in a car, they use the one that counts parts from the U.S. and Canada because that's the one set forth by law. That law requires every new car's window sticker list the percentage of its parts made "domestically."

The upshot: Determining what's "American" isn't simple anymore
Here's the other big reason fewer Detroit models made the list: There's really no such thing as a "domestic" automaker anymore. 

To survive, all of the automakers have had to become global businesses. And more and more often, their key products are global models.

Take the example of Ford's Focus. It's built in Wayne, Mich. -- and in Spain, and China, and Thailand, and several other factories around the world. (By contrast, the F-Series is only made in the United States.) 

Ford gets great benefits from the economies of scale. But realizing those benefits means that parts for the Focus you can buy here may have come from all over the world. 

That's great for Ford, which, after all, is still an American company. But it means that determining what is -- and isn't -- an "American" car isn't as simple as it used to be.