On the eve of the announcement of what may be Steve Jobs’ magnum opus, the Apple tablet, mobile advertising network AdMob charted the rise of the company’s last blockbuster product, the iPhone, and how it was the catalyst for rapid growth in the mobile ad market.

AdMob points out that it wasn’t necessarily the phone itself that triggered growth in mobile advertising, but rather successive improvements like the software development kit and App Store. As you can see, Apple’s iPhone and iPod Touch now account for more than four billion ad requests on AdMob’s network. That’s about four times what it was a year earlier, and the two product lines make up 36 percent of Admob’s total requests.

If you’re curious to learn more, last week we posted a longer analytical piece, explaining AdMob and Quattro’s success amid a sputtering economy. Both companies, which were acquired by Google and Apple respectively, prospered as developers aggressively promoted their work through advertising and as brands and premium publishers began to see mobile phones as an attractive way to reach consumers. AdMob may soon be in the hands of Apple’s emerging rival in the mobile space, Google, which agreed to pay $750 million for the company last fall. The FTC asked for more information on the deal in December, so its future is not assured quite yet.