Final answer:
The claim that 86.7% of the world's population used mobile phones by the end of 2011 is false; available data from reputable sources such as the Pew Research Center indicate lower global mobile phone penetration rates.
Step-by-step explanation:
The statement that by the end of 2011, 86.7% of the world's population was using mobile phones is false. According to data from the Pew Research Center and other sources available up to that time, the global mobile phone penetration rates were not this high. For instance, a Pew Internet report from 2011 indicated that 35% of American adults owned a smartphone. Additionally, confidence intervals provided in statistical research give us estimates of phone ownership within certain bounds, but even those did not support a figure as high as 86.7% for the global population at the end of 2011.