Last week speculation surfaced suggesting demand for Apple's popular iPhone may be slowing. That thought process was at least partially based on a report from the Wall Street Journal claiming Apple may have overestimated demand and is in the process of reducing orders for handset components.

We're still waiting to hear official numbers from Apple later this week but preliminary figures from a number of different sources seem to suggest that might not be the case at all. The latest is from research firm Kantar Worldpanel ComTech which says that for the last quarter in 2012, the iPhone was responsible for 51.2 percent of all smartphone sales in the US.

The firm points out that sales of Android handsets accounted for 44.8 percent while Microsoft's Windows Phone platform scooped up 2.6 of all smartphone sales. Kantar analyst Mary-Ann Parlato said in a statement that Apple's continual improvement is thanks to both the iPhone 5 and older models attracting various customer groups, ranging from repeat Apple shoppers to first-time buyers and those coming from competing brands.

Kartar also notes that 36 percent of iOS sales in the US came from users switching from other platforms - most notably, Android. Specifically, 19 percent of new iOS users in 2012 were previously carrying around an Android handset. That figure is up 10 percent year-over-year, we are told. 35 percent reportedly upgraded from a previous model while another 30 percent were first time smartphone buyers, according to Kantar.