Combining a Grand Total with the Original Data

*** Output grand total of sales into a data set;
Proc means data=videos;
      var sales;
      output out=summarydat sum(sales)=grandtotal;

*** Combine the grand total with the original data;
data videosummary;
      IF _N_=1 THEN SET summarydat;
      SET videos;
      percent=sales/grandtotal * 100;


Output:

sales grandtotal percent
1930 12880 14.9845
2250 12880 17.4689
...