Why Apple is so volatile by Philip Elmer-DeWitt @FortuneMagazine July 26, 2015, 8:21 AM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons “If you’re wondering why the stock is volatile,” tweeted Andreessen Horowitz’ Benedict Evans late last night, “this is everything you need to know.” What Evans offers his 82,000 followers is the attached roller-coaster chart of Apple’s 12-month trailing revenue growth from September 2004 to July 2015. It’s a picture of the rate at which Apple has been able to grow its business over the past decade or so. There’s that peak after the 2004 launch of the iPod. There’s a smaller peak after the first-generation iPhone. There’s that big peak after iPhone sales took off and deferred revenue began to kick in. Evans doesn’t offer an explanation for the falloff after 2012—that would take more than 140 characters—but the decline corresponds neatly with the 2012 drop in Apple’s share price. (See below.) “Interesting it follows a pattern,” wrote one of Evans’ Twitter followers. “It’s not ‘chaotic’.” Follow Philip Elmer-DeWitt on Twitter at @philiped. Read his Apple AAPL coverage at fortune.com/ped or subscribe via his RSS feed.