Horace Dediu, analyst and financial blogger at Asymco, provided several fascinating charts at the end of last week that not only show how dramatically iPhone activations have increased over time, but also how the U.S. market makes up a shrinking portion of that overall market. As Apple 2.0 editor Philip Elmer-Dewitt noted in an analysis of Dediu's numbers, "The U.S. is becoming a progressively less important market for sales of Apple's most valuable product line."

While the chart above shows that the percent of iPhone sales outside of the U.S. actually fell during the last quarter, this trend should reverse in the near future. It's expected that Apple will report another sharp increase in international sales after this quarter is complete, since there has been unprecedented demand for the iPhone 4S since it went on sale in China last month.

The emphasis on the international sales numbers doesn't mean that the U.S. market is by any means saturated with iPhones. In fact, the chart below shows just how much iPhone activations rose during the last quarter of 2011 in the U.S. alone. The increase in the worldwide activation numbers is just as staggering.