Beside each X value is indicated the frequency (number of time the potential score occurs in the data). Usually the variable name is used as the heading of the scores column (or the letter X), and an "f" is the heading of the frequency column.
Note that the X values in the table represent the scale of measurement, not the actual scores. For example, in the table to the right the number 10 appears only once, even though the score was obtained twice. Also, the number 5 appears even though it wasn't an observed score.