Apple TV isn't even a TV and it still made more than $1 billion in sales for the company in 2013. According to estimates, Apple sold 10 million Apple TVs at $99 each to reach that staggering number. As a result, Apple TV is now the company's fastest-growing category.

Naturally, Tim Cook was pretty pleased when he announced these impressive sales figures at the annual shareholder meeting on Friday. Apple's TV business was long-regarded as something of a "hobby" for the tech giant, but now that it is so successful, that could very well change.

"That hobby was over a billion dollars of revenue last year," Cook said. "It's a little hard to call it a hobby anymore."

According to analyst Horace Dediu of Asymco, Apple would have had to have sold 10 million Apple TVs in 2013 to reach that total sales figure of $1 billion, since each media-streaming box costs $99. He also figured out that Apple has sold 28 million units since 2007, amounting to as much as $3.5 billion in sales.

Additionally, due to the fact that Apple only sold 5 million units in 2012, the Apple TV business increased sales by 80 percent year over year. Consequently, Apple TV is now the company's fastest-growing business.

In light of these astonishing figures, perhaps Apple will finally invest in its TV business. It has been quite some time since Apple released a new version of its media-streaming box and a new piece of hardware is long overdue. This past year, Apple depended on new partnerships with media companies and the increase of Netflix subscribers to drive Apple TV sales. However, that strategy won't work if Apple wants to keep the ball rolling.

In order to be a success in the TV business, Apple needs to release an updated version of its TV box with improved capabilities and new features. Recent rumors suggest that this is indeed Apple's plan. If Apple makes a new TV box, it should arrive this spring, just in time to preempt the much-rumored AmazonTV.

Of all the companies who could compete with Apple in the media-streaming TV business, Amazon is probably the one most capable of emerging victorious. Amazon has a huge infrastructure of media and a big user base upon which to build a TV empire. Much like Apple's App store, Amazon's store is chock full of TV shows, movies, music and games - all of which would be ideal for streaming onto the big screen.

If Apple wants to keep growing its TV business, it better act fast. Should reports of Amazon's TV prove true, it would arrive in March of 2014 to challenge Apple TV.