I hope we're talking about US sales? Granted, they were way down at the bottom. But they have been growing steadily at 50-60% for the past 3 years or so, ever since the introduction of the A4. BMW has been growing too, but nowhere near that rate. I estimate that in a couple of years Audi will sell just as many cars in the US as BMW does.
A little research can save a little embarassment when posting.