Audi is celebrating the 20th anniversary of the A4 which is being hailed as the "most successful Audi of all time."

Audi is celebrating the 20th anniversary of the A4 which is being hailed as the "most successful Audi of all time."

Over the course of the past two decades, Audi has sold more than six million A4s including more than two million units of the current generation model. The company goes on to say demand is particularly strong in China, the United States and Germany where every fifth car delivered to customers is an A4.

According to Audi Production Board Member Dr. Hubert Waltl, "When the Audi A4 superseded the successful Audi 80 series 20 years ago, it became a bestseller soon after its launch. It was the fastest production ramp up in the company’s history."

Besides celebrating the model's 20th anniversary, Audi confirmed the Ingolstadt is plant is currently preparing for the next-generation model which will be launched in 2015. The company declined to elaborate but said "Numerous construction changes and other modernizations are necessary for the new model. In the new body shop in the northern part of the plant site, for example, more than 1,300 machines such as robots and welding guns are being installed."

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