I noticed that the code for OCC and IND have changed since 2007 for 3 times. If I want to compare all the data from 2007 till now, is there any universal code that can be used?
I noticed that the code for OCC and IND have changed since 2007 for 3 times. If I want to compare all the data from 2007 till now, is there any universal code that can be used?