$40 per user per year; that's the centerpiece of a new report recently released from Asymco that takes a closer look at the income, the outgo, and the numbers behind one of the most popular services currently running for mobile device users today: iTunes. But there's a lot more to the Asymco report than just the numbers breakdown, as several bits of information came out as excerpts from the report.

The Asymco report breaks things down nicely. Not only did Apple's (News - Alert) iTunes recently see a new high in terms of quarterly revenues as said revenues cleared the $4 billion mark for the first time, Apple reportedly believes that it can keep this breakneck pace going. How can that happen? Apple said that it has a "$16 billion annual run rate," which basically means $4 billion a quarter on average for the rest of its operation.

Going into that impressive number of quarter figures was iTunes' content portion, which was up from $2.1 billion previously to $2.4 billion this year. That jump was, reportedly, spurred on at least partially by the redemption of iTunes gift cards purchased during the holiday shopping season. But revenue growth, the report further noted, has been comparatively steady with regular advancements averaging about 29 percent a quarter for the last six years.

Part of what's fueling the growth of iTunes is its rapid expansion into worldwide markets. Music, for example, is currently found in 119 countries with a catalog of 35 million songs. Movies are gaining, with 109 countries getting access to roughly 60,000 titles. iBookstores are likewise bringing out a wide slate of offerings with 1.75 million iBooks available to the residents of 155 countries. Essentially, the App Store's maximum reach is about 90 percent of the entire planet, as the residents of those 155 countries combine to make up a huge swath of the planet. Meanwhile, app development is still on an upward bend, with more than 850,000 total apps available, and nearly half of these--350,000 total--made exclusively for the iPad.

Just to underscore the growth of the App Store, Apple recently rolled out a special contest to help the App Store reach the 50 billion mark for total app downloads. The one who hits the mark gets $10,000 worth of App Store products and the next 50 downloads each get $500 worth.

All of this comes together to get us to the aforementioned centerpiece of the Asymco report: 500 million total iTunes users, with an average total spend of $20 billion a year once all the various gross sales numbers are combined--apps, software, books, videos and so on--means, roughly, each user spends about $40 on average every year on iTunes.

Some, not surprisingly, question the numbers, especially when all the necessary costs to put out iTunes and its various offerings get involved. But still, one thing is quite clear: iTunes is seeing some impressive growth patterns especially given the overall state of the global economy. Call it a combination of several critical figures at once: reductions in travel, rising gas prices, improvements in home broadband, an increased number of online offerings, more people looking for alternatives to cable, and the increasing proliferation of mobile devices. But the Asymco report makes it clear: iTunes is rapidly becoming a more popular destination for a lot of people for one reason or another, and taking note of this trend may well pay off dividends in the long run for those who offer app development, e-books or the like.