fnormal

The smooth fnormal option work just like the frequency option, but produces a normalized histogram. It makes the data monotonic in x and normalises the y-values so they all sum to 1. Points with the same x-value are replaced by a single point containing the sumed y-values. To plot a histogram of the number of data values in equal size bins, set the y-value to 1.0 so that the sum is a count of occurrences in that bin. This is done implicitly if only a single column is provided. See also smooth.dem