The program below is about finding the values below the percentage and split them into five different output files. This works great for small input data files. But when I am trying to run it for a big data it takes ages to compute. Any suggestions to optimize the program so that I can get fast computation.

code:

The program below is about finding the values below the percentage and splitting them into five different output files. This works great for small input data files. But when I am trying to run it for a big data it takes ages to compute. Any suggestions on optimizing the program so that I can get fast computation?