You have to generate as many addresses as the number of addresses and transactions you had under History before. the snapshot. Could be 10, could be 50 etc.
Do you remember the other addresses with a balance?
Search for the first 10 letters of them in this list: https://ipfs.io/ipfs/Qmeb4B5AEi5MWTreKPRtufBFRFWRVTpZkBpX6FeaXCAe3B
If they have the tag KEY_REUSE: you had iotas on addresses that you reused multiple times
(used address A for sending, then received iotas to it, used it for sending again and so on)
Those iotas could have been stolen by a hacker and thus were transferred to a safe address of the Foundation. The next wallet version will give you an option to claim them back.