think about the countless people that went through the underdground cells of lubjanka and butyrka. read about the people disappearing without any fair trial in countless working prison camps - from way before the war to way after the war.
No, you wrong, the exact number of the victims of Stalin repressions is very precisely counted. Strangely enough but the bolsheviks were good accountants. There is a dossier for every disappeared victim. There is a small problem - this number is not big enough to satisfy modern West anti-soviet (read "anti-Russia") propaganda.
You can read about it here: Легенда о количестве жертв сталинских репрессий (Владимир Иванов 57) / Проза.ру - национальный сервер современной прозы