Flurry Analytics began measuring mobile usage and helping developers sell ads when the iPhone was barely a year old and Apple had not yet launched the App Store.

Today Flurry measures the activity of more than 1 billion active mobile iOS and Android devices a month, and to celebrate its fifth anniversary Wednesday it posted the chart above, part of a report titled It’s an App World. The Web Just Lives in It.

Among its findings:

• Americans who own smartphones or tablets spend, on average, 2 hours and 38 minutes “glued” (Flurry’s word) to their mobile devices.
• Only 20% (31 minutes) of that time is spent on a mobile browser — which as far as Flurry is concerned is now just another app.
• More than 50 of those minutes are spent playing games — the single largest category of apps.
• Nearly half an hour is spent on Facebook. Twitter and the other social networking apps account for less than 10 minutes.
• About 19 minutes are spent on Apple’s Safari browser, six and a half minutes on Google’s Android browser and a little more than three minutes on Opera Mini.
• E-mail is categorized under Productivity — three minutes total.

The full report is available on the Flurry blog.