What am I doing wrong?

[ichabod801]

In checkRawData, you are updating filtered_data. But that is only ever one year. You just keep changing what year it is. You either need filtered_data to be a list, which you initialize to empty at the start of checkRawData, and append to each time through the loop; or you need to write in the loop in checkRawData, not in a separate function.

Note that your function calls are redundant. At the end of the program you have three calls:

• readFile(), but you don't do anything with the return value.
  
• checkRawData(), which calls readFile() again, and you don't do anything with the returned filtered_data.
  
• writeFile(), which calls checkRawData() again, which calls readFile() a third time.
  

At the end of the file you just need one call to the top level function, currently writeFile.