# How many apps do Android and iOS users download?

Both Apple and Google give occasional numbers for cumulative downloads of apps on their respective smartphone platforms. These are generally round numbers and they're often given at scheduled events (quarterly results, developer conferences), so we don't know how precise they are (did it pass 25bn yesterday, last week or last month?), but they're still useful. I've plotted the data sets in the scatter chart below: the wobbles in the lines are probably more to do with this precision issue than actual user behaviour.

Android started later and is catching up in cumulative terms. Both are now at or around 50bn: Apple announced 50bn on 15 May and Google announced 48bn on the same day at Google IO.

What does this look like on a monthly basis? It's possible to build a model that interpolates the run between the data points we're given to work out what the monthly run rate would have to have been. This isn't perfect, but it's all we have. The chart below shows my model's output for Google Play laid over the data from Google itself, to illustrate the process; I've done the same for Apple.

Working this through, we can infer:

• Android app downloads on Google Play in Q1 2013 were about 9.75bn
• iOS app downloads were about 5bn (conveniently, Apple stated 40bn in December and 45bn in March, which makes the maths easy even for a history graduate like me).

How does that relate to users, though?

If we take trailing 24m unit sales as reported by Apple, the iOS base was 400m at March 2013 and 370m in December, giving an average for the quarter of 385m. Hence there were an average of 13 app downloads per live iOS device in the March 2013 quarter.

Android is a bit trickier, for two reasons. First, to get to an active base we again have to rely on interpolating cumulative numbers, in this case Android activations, with the same precision problem. Doing this, and taking the same trailing 24m sales, my model says there were 590m live Android devices at the end of 2012 and 680m at the end of March, an average of 635m. This implies an average of 15 downloads per live device in the quarter. Given the degree of imprecision in the model, this is probably close enough to be the same.

Just to repeat - the data is not exact enough for these to be more than reasonable approximations. It's quite possible that Apple is at 15 and Android at 10, or the other way around.

But then there's the second problem: Google's data, both for activations and downloads, does not actually give the fully picture for Android:

• There are many third-party Android app stores, including Amazon's, for which we have no data, and piracy also appears to be more widespread on Android
• Android in China is largely absent from both activations and installs, since most Android in China is sold without any Google services and so never appears in Google's statistics

Finally, of course, we have no hard data at all for Google Play revenue. Apple gives cumulative revenue on the same basis. This allows me to estimate that gross revenue on the app store (i.e. including Apple's commission) is running at about \$1 a month per live device, and has been stable for at least a year. Google is not so forthcoming.

Finally, these numbers are accelerating. Apple did 5bn downloads in the three months from December 2012 to March 2013, and then another 5bn from March to 15 May. The lack of precision means we can't say this was double the rate, but the trend is clear, and it looks the same at Android, which announced 'over 2.5bn downloads' in the last month' For all the talk of HTML5, apps are as popular as ever.

Note: both Apple and Google derive these numbers properly. Updates, re-downloads and downloads to a second device are not included. It's one download per user account per app. Matthew Panzarino at The Next Web went and asked