The TPSPLINE Procedure

If one variable in your input data set represents the frequency of occurrence for other values in the observation, specify the variable’s name in a FREQ statement. PROC TPSPLINE treats the data as if each observation appears times, where is the value of the FREQ variable for the observation. If the value of the FREQ variable is less than one, the observation is not used in the analysis. Only the integer portion of the value is used.