title: R Histogram Display x-axis ticks as percentages
body: <p>I have an R histogram where I have breaks set to a constant value (<code>breaks=16</code>). How would I display the x-tick values in the histogram as a percentages rather than decimals? </p>
  
  <p>I was thinking of writing over the x-axis with a custom one, but am not sure how to do this when breaks are set to a constant value.</p>