And doubling every year:

January 2011: 0.24%

January 2012: 0.41%

January 2013: 1.07%

Not-quite January 2014: 2.54%

Which means that it will be ubiquitous within 5 years, if it carries on this trend.

2015: 5%

2016: 10%

2017: 20%

2018: 40%

2019: 80%

Not quite ubiquity. Also, expect some flattening of the growth rate.

I actually expect it to accelerate. Once it has significant takeup you start to look bad if you don't support it, which will add to the drivers for ISPs to implement it.