You have to be careful when reading the data, because the missing observations are just coded as special numbers, and you might process the data as if it were actual accounting data rather than a missing observation code. Code Meaning -0.001 Data not available. Not Meaningful -0.004 Combined Figure. This item is combined into another data item. If the data is only available on a semi-annual basis, then this code appears in the first and third quarter.
Actual data appear in the second and fourth quarters.
Probably the easiest way to do this code checking is to assign all of your variables to an array and then check the array. This requires a lot of typing at the start, but makes processing the data easier in the long run. Once you have assigned an array, you can reference the variables just like in fortran. The semi-annual figure won't appear on the annual files, so you don't have to worry about that.