A graph of cumulative iPhone sales shows that about half the total were sold in the last two years (1). In November 2013, Horace Dedieu of Asymco fit the sales

A graph of cumulative iPhone sales shows that about half the total were sold in the last two years (1). In November 2013, Horace Dedieu of Asymco fit the sales trend to a logistics curve (2), but in August 2016 showed even faster adoption (3) Tim Cook's enthusiasm seems warranted. (1)https://infographic.statista.com/normal/chartoftheday_5390_cumulative_iphone_sales_n.jpg https://infographic.statista.com/normal/chartoftheday_5390_c... (2)http://www.asymco.com/2013/11/25/one-billion-ios-devices/ http://www.asymco.com/2013/11/25/one-billion-ios-devices/ (3)http://www.asymco.com/wp-content/uploads/2016/08/Screen-Shot-2016-08-17-at-9.23.26-PM-620x442.png http://www.asymco.com/wp-content/uploads/2016/08/Screen-Shot...