FORTUNE — Buoyed by increasing car sales and the devaluation of the Yen, Toyota Motor TM posted profits of $17.9 billion for its fiscal year 2014, up 88% from $9.5 billion a year earlier. The Japanese automaker’s car sales were up by nearly half a million units for the year, totaling 10.1 million cars sold compared to 9.7 million the previous year.

This included increased sales in all regions except for Asia.

In a press conference yesterday in Toyko, Toyota president Akio Toyoda focused on controlled growth, rather than trying to move too quickly. “I believe that sustainable growth means growing steadily each year under any circumstances,” he said. Toyoda acknowledged that his company was unprepared for the increase in vehicle sales and had trouble keeping up. “Our employees and partners were overstretched,” he said.

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Toyoda compared the company to a tree that grew too rapidly, that as a result was not able to form a strong enough trunk to protect it from the elements.”

It will be hard sustain the massive growth in the coming year, said Stephen Brown, managing director at Fitch Ratings, because the Yen’s devaluation was a one-time occurrence and because of increasing corporate taxes in Japan. “They’ve got some headwind pressures going forward now,” he said, as opposed to the help the company got last year from the currency devaluation.

The decline in Asian sales could be due to an increasingly difficult market in Thailand. Brown noted that the political turmoil in that country has created problems across the industry.

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A factor that could lift sales, especially in North America, is the planned redesign of the Camry, typically a big seller. The previous iteration of the sedan was generally viewed as “conservative,” especially when compared to cars like the Hyundai Sonata and the Ford Fusion, Brown said. “The high level reviews have been fairly positive,” he said. “That should boost their sales here.”