NEW YORK (CNNMoney.com) - The latest auto sales numbers raise the question whether the Big Three should now include Toyota Motor rather than Chrysler Group parent DaimlerChrysler.

For the first time in history, Toyota in April ranked No. 3 in terms of U.S. sales. There had been previous months that the leading Japanese automaker saw more U.S. sales than Chrysler Group, but in those cases Chrysler officials had correctly pointed out that the comparison was unfair because it included Toyota's luxury Lexus brand but not DaimlerChrysler's Mercedes-Benz division.

Photo Gallery See more photos

That distinction was lost in the most recent report, as Toyota Motor (up $0.16 to $121.19, Research) sales rose 4.5 percent to 219,965 vehicles in April, while DaimlerChrysler (down $0.52 to $53.89, Research) sales fell 6.2 percent to 211,395. No. 1 General Motors said April sales slipped 10.7 percent on an unadjusted basis to 339,796, while Ford Motor, the No. 2 automaker, said overall sales slipped 7 percent to 262,722. (Full story.)

The U.S. market is the largest market for both Toyota and DaimlerChrysler, but Toyota has far more worldwide sales than its German rival. In fact most analysts expect Toyota to pass GM (Research) later this year as the No. 1 automaker in terms of number of vehicles sold worldwide.

Toyota is growing U.S. sales at a healthy pace, up 6.6 percent since the beginning of the year, but it may not be able to stay ahead of DaimlerChrysler in U.S. sales for the full year. The Japanese automaker's year-to-date U.S. sales are 8 percent behind DaimlerChrysler's. And unlike GM and Ford (Research), which have both seen sharp declines in U.S. sales so far this year, DaimlerChrysler year-to-date sales in the U.S. are flat, despite the drop in April.

For most experts, though, it's only a question of when, not if, Toyota will pass DaimlerChrysler for good.

"I don't think it's temporary," said Dave Lucas, vice president at the auto sales tracking firm Autodata. "Toyota at this point just has the product lineup and continues to pump out the volume."

Part of Toyota's strength, according to Lucas, is having a line of vehicles that boast fuel efficiency, such as the Toyota Camry and the hybrid Prius, at a time when gasoline prices are flirting with record levels.

"Toyota seems to have the product available when people want them," said Lucas.

At the same time, said Lucas, Chrysler has experienced success with such passenger cars as its 300, as American consumers begin to switch from SUVs to more traditional vehicles.

"They've been the first traditional domestic (automaker) that has realized this is where the market is heading now," he said. "Americans are rediscovering cars and (Chrysler is) doing that better than GM and Ford."

Toyota execs have downplayed the idea of the automaker becoming a member of the Big Three, instead suggesting that the automotive industry should be looked at from a global perspective.

"Instead of the Big Three in Detroit being the symbol of the world's automobile industry, we'll be looking at a global Big Six or maybe a Big Seven, and eventually they'll all be around the same size" in North America, Jim Press, the president of Toyota Motor Sales U.S.A., told the Los Angeles Times late last year.

In addition to the traditional Big Three and Toyota, the other automakers in this group could be Japan's Honda Motor (Research) and Nissan (Research), and Korean automaker Hyundai.

________________

The incredible shrinking car companies. Read more.

For more news on autos and automakers, click here.