The 2011 gross sales of all firms in a large city have a mean of$2.5 million and a standard deviation of$0.6 million.

The 2011 gross sales of all firms in a large city have a mean of $2.5 million and a standard deviation of $ 0.6

 million. Using Chebyshev's theorem, find at least what percentage of firms in this city had 2011 gross sales of $1.2

 to $3.8 million.

Round your answer to the nearest whole number.