Microsoft's share of the browser market has declined steadily during the past 12 months while Chrome's has risen. What their current shares are depends on whose figures you choose.

I was stopped in my tracks by by the  news headline:

For the first time, Microsoft's Internet Explorer falls below 50% in browser market share

that appeared today on TNW.

It gave me a real sense of deja vu - and sure enough I found that I written a very similar news item Internet Explorer has less than 50% of the market over a year ago.

Which of us is right?

Well it's a case of whose figure you rely on. TNW presents this graph from NetMarketShare:

(click in graph to enlarge)

My information last October came from from StatCounter.

If you look at the corresponding Top 5 Browsers graph for the period October 2010 - October 2011, you can see that StatCounter shows Internet Explorer starting the twelve-month period below 50%.

(click in graph to enlarge)

So whose figures can we trust?

Well both companies' statistics are based on their client websites and so they will be biased in different ways.

But while the size of the initial share differs, as far as Internet Explorer in concerned the graphs tell a similar story of  steady decline.

According to NetMarketShare its share has gone down from 57.09% in December 2010  to 49.58% in October 2011 while StatCounters' estimate for October 2011 is 40.18 compared to 49.21 twelve months ago.

Both NetMarketShare and StatCounter show a decrease in the Firefox share, but while the former shows a very slight decline 233.69% to 22.52% the latter has a more marked one - 31.24% to 26.39%.

Both companies show Chrome as being on the increase but again they differ in their estimates of the overall share. While StatCounters' figures show a doubling from 12.39% to 25% in the space of the year to October 2011 NetMarketShare's go from 9.98% in December 2010 to 16.59% now.

Safari in 4th place shows an increase on both sets of figures and ends up either 5.93% (StatCounter) or 5.43% (NetMarketShare) while bottom of the league  Opera shows a downward trend on both, to 1.81% (StatCounter) or 1.56% (NetMarketShare).

So the overall message is that Internet Explorer is in decline but it still hold the largest single share of the market and you need to cover IE, Firefox and Chrome to reach over 90% of it.

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