AT&T and Verizon’s recent sales figures show some interesting trends. Namely, a comparison between Android-powered smartphones and the iPhone demonstrates that while the former appears to have flatlined in terms of growth, iPhone sales are continuing to spike and increase each time a new model is released.

As such, it seems apparent that Apple’s iPhone, rather than the countless different Android-powered smartphones available, is helping both AT&T and Verizon grow as operators.

Smartphone sales for AT&T and Verizon.

The above chart, compiled from both carriers’ recent sales figures by Ben Evans, says it all.

As Evans explains, in the chart the handset sales labeled “other” are made up almost entirely of Android-powered smartphones manufactured by the likes of Samsung, HTC, et al. Yet despite their variety, it appears that Android smartphone sales with AT&T and Verizon have flatlined, and show no sizeable quarterly increase.

The iPhone’s sales, however, are markedly different. Coinciding with the release of new models in the fall of 2011 and 2012, both AT&T and Verizon saw a spike in iPhone sales. This seasonal increase has driven iPhone growth over the course of both years.

On the basis of the above data, Evans draws three sensible conclusions:

First, Android isn’t really growing at all in the USA, at least at the big two operators. (‘Other smart’ is almost all Android now). All the growth is coming from iPhone.

Second, there’s near-zero seasonality in Android phone sales. People decide they want a phone and go out and buy whatever’s in the shop at the time that looks good. Launches of ‘hero’ Android phones appear to have no impact at all – they may take share from other Androids, but not from iPhone and they don’t increase overall sales.

Third, there seems to be a complete disconnect between Android and iPhone purchasing. One can understand iPhone sales per se going up in a launch quarter, but why don’t Android sales go down in those quarters? It looks like a new iPhone launch doesn’t tempt in Android buyers at all.

However, as Evans himself admits, the chart doesn’t show one integral aspect – what he calls a “churn within the Android base: Android users moving to iPhone while new non-smart buyers shift to Android, keeping the sales steady.”

Nevertheless, his conclusions are still apparent. Though it will of course be interesting to see whether the HTC One and Samsung Galaxy S4 have any impact on the above hypotheses.