Independent market analysis firm Kantar Worldpanel has published its latest monthly data for sales in several key smartphone markets around the world, including the US, China, and the EU5 - the top five European Union markets of Great Britain, Germany, France, Italy and Spain.

The latest data, for the three months ending in January 2017, shows further growth for iOS in most key markets, while Android also increased its global smartphone sales share in nearly every major market except for the United States.

Meanwhile, Windows' share of the mobile market fell further around the world, as it has continued to do over the last two years. Kantar has now effectively written off Windows in the smartphone market:

Gone are the days when a BlackBerry OS, Symbian, or Windows Mobile could make a significant impact. It is clear that there will only be two smartphone ecosystems moving forward – iOS and Android. To succeed, phone manufacturers will have to play by those rulebooks.

Kantar highlighted the recent Mobile World Congress industry expo as evidence of the new "two-OS world". BlackBerry, which previously had its own operating system, is no longer making its own devices, licensing its brand for use on handsets running Android instead, including the new KEYone unveiled at MWC. Nokia, which was the largest Windows Phone manufacturer, has gone down a similar path with its new 3, 5 and 6 Android smartphones, developed by HMD Global.

Microsoft is rumored to be developing a new class of mobile device with powerful hardware, and a multi-purpose user experience that will support desktop-class x86 applications when the handset is connected to a dock and external monitor. Some believe that the company will deliberately avoid describing the device as a "phone", distancing itself from its smartphone struggles.

Kantar clearly believes that Microsoft is done in the smartphone market, and that Android and iOS are now the only viable platforms. It remains to be seen if the semantics of how Microsoft's next-generation device is labelled will help it to prove the analysts wrong. For now, let's take a closer look at how all three major operating systems have been performing recently in some of those key markets.

Android's smartphone sales market share fell slightly in the US by 1.8 percentage points (pp) year-over-year (YoY), from 58.2% to 56.4%. During the same period, iOS increased by almost 3pp to 42% share.

Kantar notes that 70% of the US market is dominated by Apple and Samsung, leaving LG in a distant third place with around 11% share. It doesn't believe that the launch of LG's new G6 flagship - which was unveiled at MWC - will "have a significant impact" on its US market share, despite the fact that its high-end dual-display V20 was the company's "best selling device in the US" during the three months ending in January.

Meanwhile, Windows' share of the US smartphone market halved YoY to just 1.3%.

The scale of Microsoft's mobile decline was much greater in Great Britain, where its share fell from 8.6% to just 1.9% YoY. Some of that share was lost to Android, which grew by 1.8pp to 54.4% over the same period, but the big winner there was iOS. Apple's mobile devices now account for 43.3% of sales in Britain, an increase of 4.7pp YoY.

BlackBerry OS is clinging to 0.1% share there, down from 0.2% a year earlier.

Across the Channel, in France, it was a very similar story for all major platforms. Android sales share increased slightly, by 1.1pp, to 72.9%, while iOS grew its share by considerably more, rising by 4.9pp from 19.3% to 24.2% YoY.

Windows' share plummeted from 7.8% to 2.8% over the course of the year, while BlackBerry crumbled from 0.5% to just 0.1%.

Germany used to be one of Windows' stronger markets for smartphone sales, peaking at around 10% share in mid-2015, making it one of the few countries in which Microsoft's share reached double-digits. Many of the devices sold there were higher-end too, with sizeable sales for the Lumia 920 and 930 handsets. But by January 2016, its sales market share there had fallen to 5.9%, and has more than halved over the year since then, to 2.9%.

As in Britain and France, Android market share increased slightly in Germany, where Google's OS now runs on three out of every four smartphones sold. iOS also grew by 2pp to 21.3% YoY.

Android is doing even better in Italy, where its share is now at 79%, up very slightly compared with a year earlier. iOS has also grown by a modest amount over the last year, rising by 1.4pp to 15.8%.

Windows' YoY losses weren't quite so bad in Italy, where it dropped by 2.8pp, from 7.2% to 4.4%, making it one of the platform's most popular markets at the present time. But Italy was once Microsoft's biggest mobile market, with over 17% share in December 2013.

Spain has never been a strong market for Windows phones, so the YoY fall from 0.8% to 0.4% is of little consequence. Notably, iOS also lost market share there over the same period, though, dropping by 1.2pp to 10.2%.

Android dominates the Spanish mobile market, with its share now approaching a staggering 90%.

But in China, Android's share rose by a whopping 9.3pp YoY to 83.2%. iOS was the biggest loser there, falling from 25% to 16.6% across the year.

Despite this, Kantar said that the "iPhone 7 remains the top-selling smartphone in Urban China", but the largest vendor by far is Huawei, with 26.6% share.

You can check out the smartphone sales market share over time for these markets, and others, with the interactive Kantar Worldpanel ComTech visualization tool.