Understanding Society User Support

I'm working out the ethnic group in Wave 3, but I notice that most of them are "inapplicable". I knew that it only provides "new entrant never interviewed" in Wave 3. When I tried to merge the information from Wave 1 and Wave 2, I noticed that there are about 10 thousands people "Lost to follow up" between wave 1 and wave 2 for a_indresp data (individual dataset); and there are also about 10 thousands people "Lost to follow up" between wave 3 and wave 2 for b_indresp data. I'm a bit uncertain about these number are right. Can you let me know where I can get some report or documents to prove these or get the right number?

Thank you!