Can I block whole countries?

So…can I block certain countries all of a sudden?
Failed logins, using non-existing usernames and so forth…98% are coming from one country. Yes I know about VPN.

The way my settings are:

1) If you login fail twice, you are banned.
2) If you use an username that does not exist, you are banned.
3) If you use admin as username, you are banned.

The ban lasts for 5 years (whatever that is in minutes, I can’t remember right now).