The US is on the verge of having a 90% smartphone penetration by August 16,2016 . According to Horace Dideu of Asymco The adoption of smartphones in the US is on track for reaching 90% of the available audience by August 2016.
This is a mere eight years after smartphones reached 10% penetration, which means Smartphone adoption in US grew 900% in eight years. The below charts shows the How American Consumer adoption of technology has changed exponentially from 1962 to 2013
In the chart above "The mobile growth and adoption in US" has been compared with other consumer technology adoption, including the adoption and growth of TV, Fridge , AC, dishwasher, Microwave , VCR,PC, Internet growth and subsequently " Mobile, Smartphones and Tablets
So while it took 27 years for consumers to move from TV to internet, 1966 to 193,14 years to move from Feature phones to Smartphones.
In comparison it the adoption of Smartphone by 50% US consumers took a mere 5 years, (2007 to 2012) and it will take a mere 2 years for this to reach 90%