The percent of people in the United Kingdom who watch video content
on their mobile phones can be modeled by
P(t) = 13.86t^0.535

where t = 0 corresponds to the year 2011.

A) What percent of the U.K. population was expected to watch video
content in 2015?

B) How fast was the percentage of viewers changing in 2015?

If needed, round your answer to 4 decimal places.