text: If I understand correctly, the figures given in the sales report are actual figures, not estimates based on a sample.  In this case, the percentages are exact and do not have variance or standard deviation.  They are actual statistics, not estimates.
  
  @Keala R. Kaanui's point is that 27% and 30% are both "a high percentage."  
  
  You can agree or disagree with that characterization, just not on the stated basis.